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PubMed1999

Synthesis of beta-D-Galactosyl Ceramide Methylene Isostere.

The methylene isostere of the glycosphingolipid beta-D-galactosyl N-palmitoyl C(18) ceramide has been synthesized by a linear reaction sequence starting from a beta-linked D-galactopyranosyl aldehyde. First, this sugar aldehyde was converted into a methylenephosphorane which in turn was coupled with N-Boc serinal acetonide. The double bond of the resulting olefin was reduced and the oxazolidine ring was cleaved and oxidized to give a C-glycosyl N-Boc alpha-amino butanal (three-carbon chain elongation). Then, an additional C(15) carbon chain was installed by addition of lithium 1-pentadecyne to the above glycosyl amino aldehyde. The syn/anti ratio (70:30) of the resulting mixture of amino alcohols was reversed (5:95) by an oxidation-reduction sequence to achieve the same stereochemistry as in the hydrophilic head of D-erythro-sphingosines. The major product was subjected to the reduction of the triple bond with LiAlH(4) to give the olefin with E geometry. Finally the N-amide group was installed by reaction with palmitoyl chloride and the O-benzyl protective groups of the sugar moiety were removed by treatment with lithium in liquid NH(3)-THF. The final product was characterized as the O-acetyl derivative.

Journal Article↗

PubMed1997

Design of stable biologically active recombinant lutropin analogs.

Glycoprotein hormones are noncovalent heterodimers comprised of a common alpha subunit and a hormone-specific beta subunit. Secretion and biologic action of these hormones are dependent on the formation of the heterodimer. The human LH beta subunit is unique among the other beta subunits in that it assembles inefficiently with the alpha subunit. To bypass this rate-limiting step, we constructed the LH single chains where the carboxy terminus of beta was fused to the amino terminus of alpha subunit through a linker. Compared to the human LH heterodimer, the extent of secretion was greater for the tethers although the rate was dependent on the nature of the linker. The LH single chains were biologically active even though there was loss of recognition by a LH-specific monoclonal antibody. This suggests that receptor binding of the single chains is not impaired by changes in the heterodimeric configuration resulting from tethering the subunits. In addition, single chains exhibited a remarkably greater in vitro stability than the heterodimer, implying that these analogs will be useful as diagnostic reagents and that their purification will be facilitated.

Animals↗

PubMed1976

Non-equivalence of human hemoglobin chains in the oxidation-reduction and heme-transfer reactions. A 13C nuclear-Magnetic-resonance study.

12C nuclear magnetic resonance (NMR) spectroscopy has been applied to the investigation of chain non-equivalence for two reactions of human hemoglobin: oxidation-reduction and hemetransfer. The method is based on previous observations that in the carbonyl region, Hb13CO gives two well-resolved resonances which arise from 13C of carbonyls bound respectively to the alpha and beta chains; moreover, integration of spectra allows on e to estimate their relative abundance. A mixture of ferrous and ferric hemoglobins in dye-mediated oxidation-reduction equilibrium can be formally considered to be equivalent to two redox couples in equilibrium, namely alphaIII/alphaII and betaIII/betaII; from a knowledge of these ratios, one can conclude whether the chains are equivalent or not in their oxidation-reduction properties. In this work, these ratios were evaluated by reacting the redox systems with 13CO and integrating the 13C NMR spectra. The results show differences in the intrinsic oxidation-reduction potentials of the chains in hemoglobin tetramer, E1/2(beta)being higher than E1/2(alpha)in neutral solution but not at pH9 and above. The binding of inositol hexakisphosphate does not modify the difference between beta and alpha though substantially increasing the overall potential The results are discussed in the light of current hypotheses to account for the change of Hill coefficient with pH for the reaction studied. The non-equivalence of chains is shown also for heme transfer from methemoglobin. For the phosphate-free protein, the beta chains lose heme more rapidly than that alpha chains; the addition of inositol hexakisphosphate results in the decrease of overall heme transfer as well as of chain heterogeneity.

Binding Sites↗

PubMed1983

Biochemical characterization of collagens and of a non-collagenous protein synthesized by guinea pig lung fibroblasts in culture.

Employing various radioactive amino acids, protein biosynthesis by guinea pig lung fibroblasts has been studied in monolayer culture. The cells were shown to synthesize and secrete several collagenous and noncollagenous proteins. The biosynthesized macromolecules have been characterized employing molecular sieve and ion exchange chromatography (DEAE-cellulose column), SDS-polyacrylamide gel electrophoresis, and enzymatic digestion. It was found that the guinea pig lung fibroblasts synthesized mainly type I procollagen molecules which appeared in the media in various stages of cleavage. The intact procollagen molecules and the various processed products were identified by their electrophoretic migration in SDS-polyacrylamide slab gels and further characterized by 1) elution position on SDS-agarose columns under reducing conditions; 2) hydroxyproline content; 3) change in elution position on SDS-agarose after pepsin digestion; 4) chromatographic separation on DEAE-cellulose columns and electrophoretic mobility of the various peaks; and 5) susceptibility to collagenase digestion. Slab gel electrophoresis under non-reducing conditions of aliquots of culture media after limited pepsin digestion indicated the presence of disulfide-bonded type III collagen alpha-chains. In addition, the lung fibroblasts synthesized a non-collagenous protein composed of two disulfide-bonded chains. The individual chains appeared to have a molecular weight of approximately 220,000 when examined under reducing conditions. This protein has been identified as fibronectin based on its molecular weight, its resistance to collagenase attack, its susceptibility to protease digestion and its precipitation with specific antisera to fibronectin.

Animals↗

PubMed1996

Crystal structure of a bacterial family-III cellulose-binding domain: a general mechanism for attachment to cellulose.

The crystal structure of a family-III cellulose-binding domain (CBD) from the cellulosomal scaffoldin subunit of Clostridium thermocellum has been determined at 1.75 A resolution. The protein forms a nine-stranded beta sandwich with a jelly roll topology and binds a calcium ion. conserved, surface-exposed residues map into two defined surfaces located on opposite sides of the molecule. One of these faces is dominated by a planar linear strip of aromatic and polar residues which are proposed to interact with crystalline cellulose. The other conserved residues are contained in a shallow groove, the function of which is currently unknown, and which has not been observed previously in other families of CBDs. On the basis of modeling studies combined with comparisons of recently determined NMR structures for other CBDs, a general model for the binding of CBDs to cellulose is presented. Although the proposed binding of the CBD to cellulose is essentially a surface interaction, specific types and combinations of amino acids appear to interact selectively with glucose moieties positioned on three adjacent chains of the cellulose surface. The major interaction is characterized by the planar strip of aromatic residues, which align along one of the chains. In addition, polar amino acid residues are proposed to anchor the CBD molecule to two other adjacent chains of crystalline cellulose.

Amino Acid Sequence↗

PubMedDate not supplied

Epitope contiguous chains and antibody recognition in HIV-1 synthetic peptide antigens.

Five peptides derived from human immuno deficiency virus (HIV-1) gp41 transmembrane protein have been synthesized: M9 (610-618), M12 (598-609), M15 (600-614), M21 (584-604) and M23 (587-609). These sequences partially overlap in the region vicinal to the immunodominant epitope CSGKLIC, between two cysteine residues 603-609 and three of them (M12, M15 and M23) include this complete heptapeptide. M23, the longer peptide, includes an hydrophilic chain in addition to the heptapeptide loop. The purpose of this work was to determine the influence of contiguous chains to the heptapeptide loop on antibody recognition in fluid and solid phases, and dissociation constants (KD) of each sequence with human anti-HIV-1 antibodies. Two peptides, M13 and M23, overlapped on this loop, were found to be more reactive. Antigen-antibody dissociation constants were determined for both peptides by competition enzyme-linked immunosorbent assay, using each peptide alternatively as the solid phase-immobilized antigen. In addition to the influence of solid-phase antigen on calculated dissociation constants (a phenomenon described by Seligman, 1994), the inhibitory effect of M15 in liquid phase on antibody binding to solid phase M23 was higher than exerted by M23 in solution over antibody binding to M15 on solid phase. On the basis of peptide sequence and predicted antigenicity, this behavior appeared to be contradictory. It is assured that the possible origin of this phenomenon is due to unfavorable conformation of the longer peptide. Even though synthetic peptides mimic mainly sequential epitopes, conformational preferences in fluid or solid phase play an important role in epitope functionality. In particular, addition of residues to known immunodominant sequences may not always amplify antibody recognition if conformation provokes steric hindrance in the native epitope.

Amino Acid Sequence↗

PubMed1983

An immunohistological study of reactive lymphoid tissue.

The aim of this study was to document the patterns of cytoplasmic Ig heavy and light chain expression in reactive lymphoid tissue, using single and double immunoenzymatic labelling techniques. This investigation was undertaken, firstly, to provide information on whether the normal counterparts of high grade lymphoma cells (e.g. centroblasts, immunoblasts) ever express more than one light or heavy chain (as has been noted in the past for lymphomas) and also, secondly, to seek evidence of intraclonal 'switching' from cytoplasmic IgM to cytoplasmic IgG expression. Paraffin embedded sections, all showing substantial reactive changes, were analysed by means of immunoperoxidase stains for the three major immunoglobulin classes (IgG, IgM and IgA), both light chain classes and J chain. In addition, double immunoenzymatic labelling techniques were used to search for cells showing simultaneous expression of kappa and lambda light chains and cells expressing mu and gamma heavy chain. Large transformed lymphocytes showing cytoplasmic Ig-staining in the pulp and interfollicular areas often have nuclear morphology indistinguishable from germinal centre centroblasts. There was no evidence of primitive appearing IgM-positive cells and IgG-positive cells of more mature morphology. In addition, immunoenzymatic staining showed that cells simultaneously expressing both IgG and IgM are only rarely encountered. When such cells were detected, the morphology was not that of a blast cell, but rather of a plasma cell containing Russel bodies. Hence it is suggested that cytoplasmic IgM switching to IgG is rarely detected by immunohistological methods in reactive tissue. Double staining for kappa and lambda revealed that cells simultaneously expressing both light chain types were not detected even among cells showing the most primitive morphology.

Cytoplasm↗

PubMed1998

HbS-oman heterozygote: a new dominant sickle syndrome.

Hemoglobin (Hb) S-Oman has two mutations in the beta-chains. In addition to the classic betaS mutation (beta6 Glu --> Val), it contains a second mutation in the same chain (beta121 Glu --> Lys) identical to that of HbOARAB. We have studied a pedigree of heterozygous carriers of HbS-Oman that segregates into two types of patients: those expressing about 20% HbS-Oman and concomitant -/ thalassemia and those with about 14% of HbS-Oman and concomitant -/- thalassemia. The higher expressors of S-Oman have a sickle cell anemia (SS) clinical syndrome of moderate intensity, while the lower expressors have no clinical syndrome, and are comparable to the solitary case first described in Oman. In addition, the higher expressors exhibit a unique form of irreversibly sickled cell reminiscent of a "yarn and knitting needle" shape, in addition to folded and target cells. The CSAT of S-Oman is identical to that of S-Antilles, another supersickling hemoglobin, whose carriers express the abnormal hemoglobin at 40% to 50%, with a very similar clinical picture to HbS-Oman. Because the level of expression is so different and the clinical picture so similar, and based on the hemolysates CSAT's, we conclude that HbS-Oman produces pathology beyond its sickling tendencies. A clue for this additional pathogenesis is found in the fact that homozygous HbOARAB, which has the same second substitution as S-Oman, has a moderately severe hemolytic anemia; when HbOARAB is combined with HbS, it makes the phenotype of this double heterozygote as severe as SS. Properties of HbS-Oman red blood cells (RBCs) include reticulocytes that are much denser than normal (similar to those of SC and CC disease), a decrease in the Km for Ca2+ needed to activate the Gardos' channel (making this transporter more sensitive to Ca2+), increased association of HbS-Oman with the RBC membrane, the presence of dense cells by isopycnic gradient, the presence of folded cells, and abundant nidus of polymerization under the membrane. Other properties include a clear increase in volume and N-ethylmaleimide-stimulated K:Cl cotransport in RBCs expressing more than 20% HbS-Oman. We conclude that the pathology of heterozygous S-Oman is the product of the sickling properties of the beta6 Val mutation which are enhanced by the second mutation at beta121. In addition, the syndrome is further enhanced by a hemolytic anemia induced by the mutation at beta121. We speculate that this pathology results from the abnormal association of the highly positively charged HbS-Oman (3 charges different from normal hemoglobin) with the RBC membrane.

Adolescent↗

PubMed1987

The production of recombinant HLA-DR beta and invariant chain polypeptides by cDNA expression in E. coli.

In this report we describe the production of recombinant fusion proteins of the HLA-DRw6 beta chain and the murine Ia-associated invariant chain. cDNAs encoding the human HLA-DRw6 beta chain and the murine Ia-associated invariant chain were introduced into bacterial expression plasmids. These plasmids direct the synthesis of the respective molecules as fusion proteins of the bacteriophage MS-2 polymerase by E. coli. Fusion proteins purified from crude E. coli lysates were used to raise antisera in rabbits. These antisera were able to immunoprecipitate biosynthetically labelled class II and invariant chain antigens. Additionally, two anti-DR antisera were raised against single domains of the HLA-DR beta chain thus generating reagents with a defined fine specificity. The anti-murine invariant chain serum was shown to cross-react with the human invariant chain and therefore may be useful for studying invariant chain and Ia antigen expression in different species. The method described here permitted us to produce large quantities of immunologically relevant proteins, for use in the production of polyclonal and monoclonal antibodies. Soluble fragments of the fusion proteins representing certain DR domains may also be useful in functional immunological studies.

Animals↗

PubMed1996

Polydispersity in sulfation profile of oligosaccharide alditols isolated from the protein-linkage region and the repeating disaccharide region of chondroitin 4-sulfate of bovine nasal septal cartilage.

Proteoglycans of bovine nasal septal cartilage bear predominantly chondroitin 4-sulfate. After exhaustive chondroitinase ABC digestion of a chondromucoprotein preparation rich in proteoglycans and subsequent reductive beta-elimination, five hexasaccharide alditols were isolated from the glycosaminoglycan-protein linkage region. They were analyzed by enzymatic digestion in conjunction with HPLC and by one-dimensional and two-dimensional 1H-NMR spectroscopy. They share the conventional core saccharide structure delta 4.5HexA alpha 1-3GalNAc beta 1-4GlcA beta 1-3Gal beta 1-3Gal beta 1-4Xyl-ol (where delta 4.5HexA is 4,5-unsaturated hexuronic acid), but have different sulfation profiles. One compound (I) does not contain sulfate. Two of the three monosulfated compounds (II and III) have an O-sulfate group at either C6 or at C4 of the GalNAc residue. The other monosulfated compound (IV) is hitherto unreported and has a O-sulfate at C4 of the Gal residue preceding the GlcA residue, whereas the GalNAc is not sulfated. The disulfated compound (V) has sulfate groups at C4 of both the Gal residue preceding GlcA and the GalNAc residue. The molar ratio of compounds I-V is 38.3:5.9:43.0:1.6:11.2. The structural heterogeneity of these hexasaccharide alditols reflects the polydispersity in the linkage region of the chondroitin sulfate chains. In addition, two trisaccharide and two tetrasaccharide alditols derived from the repeating disaccharide region of the chondroitin sulfate chains were also isolated. Their structures were unambiguously determined by enzymatic analysis and by 1H-NMR spectroscopy as delta 4.5HexA alpha 1-3GalNAc(4-O- or 6-O-sulfate)beta 1-4GlcA-ol and delta 4.5HexA alpha 1-3GalNAc(4-O- or 6-O-sulfate) beta 1-4GlcA beta 1-3GalNAc(4-O-sulfate)-ol, respectively.

Animals↗

PubMed1985

The coming of age of the immunoglobulin J chain.

During the last decade the immunoglobulin J chain has indeed come of age. The amino-acid sequence has been determined for the mouse and human polypeptides, and the data obtained have established the uniqueness of the primary structure and its high degree of conservation in vertebrates. The biosynthesis of J chain has been defined: The information is encoded in a simple transcription unit that is induced by changes in chromatin structure to express a single primary transcript and a single mature message; translation of the message yields a propolypeptide which is processed and transported through the cell by the conventional pathway for secreted proteins. As a result of these advances, many of the functions of the J chain have been clarified. Analyses of the expression of J chain mRNA and protein in mouse lymphocytes have shown that the initiation and amplification of J-chain synthesis are critical steps in the pentamer IgM response because the J polypeptide is required for the assembly of the IgM antibody. Analyses of the behavior of the polymeric Igs have established that the J-chain component contributes, certainly indirectly and perhaps also directly, to the secretion of pentamer IgM and the transcellular transport of both IgM and IgA. However, knowledge of the J chain has yet to achieve full maturity. How the J chain participates in the polymerization of IgM and IgA needs to be reexamined in view of the recent findings that assembly may involve an oxidative mechanism catalyzed by a lymphocyte-specific enzyme. The observation that J chain may be constitutively expressed in human B cells and the possibility that J chain performs additional regulatory functions in monomer-Ig secreting cells should be pursued. Determination of the J-chain secondary structure and its arrangement in the polymer Fc domains is critical to understanding the effector functions of polymer Ig. Lastly, the finding that late-acting factors, such as interleukin-2, induce an amplification in J-chain synthesis opens the way to using the expression of J chain as a model system for dissecting the mechanism of gene regulation. These are the challenges for the next decade.

Amino Acid Sequence↗

PubMed1981

Hemocyanins in spiders, XIV. Subunit composition of dissociation intermediates and its bearing on quaternary structure of Eurypelma hemocyanin.

The 37 S hemocyanin (24 subunits of 7 types) isolated from the tarantula, Eurypelma californicum, was dissociated partially by various agents and the dissociation intermediates analyzed for their subunit composition by crossed immunoelectrophoresis. The subunit composition of the native hemocyanin was reexamined and the pending problem of the ratio between subunits a and g (= c2) clarified. The subunits are present in the ratio of a:b:c:d:e:f:g = 4:2:2:4:4:4:4. Breakdown products were shown to contain 19 (20?), 16, 12, 8, 7 and 6 polypeptide chains (possibly, there is also a 15-mer). The 19-mer is formed by removal of 5 monomeric subunits from one of the constituent hexamers of the native (4 x 6) hemocyanin, the 16-mer by losing one further copy each of e, f and g. The dodecamer is formed by cleavage with 2-mercaptoethanol and represents a half-molecule. The octamer could not be clearly analyzed but probably contains one copy of chain d more compared to the heptamer. The heptamer represents a one-quarter hemocyanin with one additional polypeptide chain sticking out of the hexameric structure. This can be either subunit b or c of the heterodimer bc. Only one type of hexamer was obtained after cleavage of the 37 S hemocyanin with 4M urea, containing one copy each of chains a, b, d, e, f and g. It is concluded that the 37 S hemocyanin is composed of two identical dodecameric halves linked by dimerization of subunit f, and that each half-molecule is constituted by two non-identical though similar hexamers, both encompassing a complete set of subunits a, d, e, f and g, but differing in their share of the rather stable, the 'c'-hexamer unstable. The relative positions of some of the subunits within the native oligomer are discussed.

Hemocyanins↗

PubMed1991

Kinetic chain exercise in knee rehabilitation.

Rehabilitation is recognised as a critical component in the treatment of the anterior cruciate ligament (ACL) injured athlete, and has been the subject of intense research over the past decade. As a result, sound scientific principles have been applied to this realm of sports medicine, and have improved the outcome of both surgical and nonsurgical treatment. Possibly the most intriguing of these principles is the use of the kinetic chain concept in exercise prescription following ACL reconstruction. The hip, knee, and ankle joints when taken together, comprise the lower extremity kinetic chain. Kinetic chain exercises like the squat recruit all 3 links in unison while exercises such as seated quadriceps extensions isolate one link of the chain. Biomechanical assessment with force diagrams reveals that ACL strain is reduced during kinetic chain exercise by virtue of the axial orientation of the applied load and muscular co-contraction. Additionally, kinetic chain exercise through recruitment of all hip, knee, and ankle extensors in synchrony takes advantage of specificity of training principles. More importantly, however, it is the only way to reproduce the concurrent shift of 'antagonistic' biarticular muscle groups that occurs during simultaneous hip, knee, and ankle extension. Incoordination of the concurrent shift fostered by exercising each muscle group in isolation may ultimately hamper complete recovery. Modifying present day leg press and isokinetic equipment will allow clinicians to make better use of kinetic chain exercise and allow safe isokinetic testing of the ACL reconstructed knee. Reconstruction of the ACL with a strong well placed graft to restore joint kinematics, followed by scientifically sound rehabilitation to improve dynamic control of tibial translation, will improve the outcome after ACL injury.

Anterior Cruciate Ligament Injuries↗

PubMed2004

Loss of heterozygosity at chromosome 9p21 is a frequent finding in enteropathy-type T-cell lymphoma.

Enteropathy-type T-cell lymphoma (ETL) and ulcerative jejunitis (UJ) are rare disorders often occurring in patients with coeliac disease. The genetic events associated with the accumulation of intraepithelial lymphocytes in coeliac disease and tumour development are largely unknown. Deletions at chromosome 9p21, which harbours the tumour suppressor genes p14/ARF, p15/INK4b, and p16/INK4a, and 17p13, where p53 is located, are associated with the development and progression of lymphomas. To examine whether deletions at 9p21 and 17p13 play a role in ETL, 22 cases of ETL and seven cases of UJ were screened for loss of heterozygosity (LOH) by tissue microdissection and polymerase chain reaction (PCR) analysis for microsatellite markers. Furthermore, p53 and p16 protein expression was examined by immunohistochemistry. In addition, polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis for detection of mutations in exons 5-8 of the p53 gene was performed in five cases of ETL and three cases of UJ. LOH was found in at least one microsatellite marker at the 9p21 locus in 8 of 22 (36%) ETLs, but not in UJ. Five of nine (56%) tumours composed of large cells showed LOH at 9p21, as opposed to two of eight (25%) tumours with small- or medium-sized cell morphology. The region spanning the p14/p15/p16 gene locus was most frequently affected (five cases); LOH at these markers coincided with loss of p16 protein expression in all of these cases. p53 overexpression was demonstrated in all ETLs examined and in four of seven cases of UJ. However, no alterations of the p53 gene were detected by LOH or PCR-SSCP analysis. The results of this study show that LOH at chromosome 9p21 is frequent in ETL, especially in tumours with large cell morphology; this finding suggests that gene loss at this locus may play a role in the development of ETL.

Adult↗

PubMed1989

Structural study of the sugar chains of human platelet thrombospondin.

The asparagine-linked sugar chains of human platelet thrombospondin were released as oligosaccharides by hydrazinolysis. About 12 mol of sugar chains was released from one thrombospondin molecule. This was converted to radioactive oligosaccharides by sodium borotritide reduction after N-acetylation, and separated into one neutral and four acidic fractions by paper electrophoresis. More than 90% of the oligosaccharides were recovered in the acidic fraction. The acidic oligosaccharides were mostly converted to neutral oligosaccharides by sialidase treatment, indicating that they are sialyl derivatives. The neutral and sialidase-treated acidic oligosaccharides were further fractionated by Bio-Gel P-4 column chromatography. Structural study of each oligosaccharide by sequential exoglycosidase digestion and methylation analysis revealed that the thrombospondin contains mono-, bi-, tri-, and tetraantennary complex-type sugar chains in addition to a small amount of high-mannose type. Approximately 70% of the complex-type sugar chains was fucosylated at asparagine-linked N-acetylglucosamine residue and 19% of the biantennary complex-type sugar chains was bisected.

Blood Platelets↗

PubMed1989

Relationship between structure and activity of the "ramified" region in anti-complementary pectic polysaccharides from Angelica acutiloba Kitagawa.

One of the anti-complementary pectic polysaccharides (AR-2IIa) isolated from the root of Angelica acutiloba Kitagawa gives the "ramified" region (PG-1a,rhamnogalacturonan with neutral side-chains) in addition to oligogalacturonides on digestion with endo-alpha-D-(1--4)-polygalacturonase. When the neutral side-chains in PG-1a were digested with both exo-alpha-L-arabinofuranosidase and exo-beta-D-galactosidase, approximately 70% of the arabinosyl chains and approximately 30% of the galactosyl chains were released. The resistant product E-PG-1a had the same anti-complementary activity as PG-1a. E-PG-1a gave long (d.p. greater than or equal to 5) and short (d.p. less than or equal to 4) neutral galactosyl chains after degradation of the GalA moiety by base-catalysed beta-elimination in the presence of sodium borodeuteride followed with lithium-mediated degradation. Methylation analysis showed that the long galactosyl chains consisted mainly of terminal, 6-linked and 3,6-disubstituted Gal, and that the short chains were rich in 6-linked Gal. Degradation of the GalA moieties in PG-1a markedly decreased the anti-complementary activity, but the long and short galactosyl chains still expressed approximately 50 and approximately 20%, respectively, of the anti-complementary activity of E-PG-1a.

Animals↗

PubMed1976

Carbohydrate moieties of human seminal plasma arylamidases.

Human seminal plasma contains two arylamidases that differ considerably with respect to their antigenic structures, molecular weights and electrophoretic mobilities. Both enzymes are glycoproteins with different carcohydrate moieties. With the aid of precipitating lectins, the faster migrating arylamidase I was found to possess a PHA receptor (beta-Gal-GNAc-(Man)2-GNAc) with terminal N-acetyl-neuraminic acid groups. The carbohydrate moiety of arylamidase II consists of at least 2 types of carbohydrate chains: A disaccharide (beta-Gal(1-3)GalNAc) reacting with the lectin from Arachis hypogoea and in addition a chain containing the PHA receptor. This chain probably contains a terminal neuraminic acid group and a terminal fucosly group.

Aminopeptidases↗

PubMed1997

CDRH3 length is the target of selection of disease-associated IgM autoantibodies.

The experiments outlined here provide evidence for positive selection of B-1 lymphocytes secreting IgM autoantibodies in the autoimmune mev mice as a result of the reduced threshold of responsiveness to autoantigens because of PTP1C deficiency, which is targeted at the CDR3 length of the variable region of the heavy chain. In addition, characteristic differences in the size, hydrophobicity pattern, and relative local charge of the CDR3 of the heavy chain of disease-associated IgM autoantibodies from moth-eaten mice help distinguish them from physiological natural autoantibodies present in normal mice.

Animals↗