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D C Shaw

Publications and source records attributed to D C Shaw.

At least 55 records · Page 3Linked to original sources
PubMed1987

A mild method for the preparation of disulfide-linked hybrids of immunoglobulin light chains.

A method is described for the hybridization of immunoglobulin light chains (Bence-Jones proteins) from different patients. The interchain half-cystine residues in the light chains from one subject are converted into mixed disulfides with 2,2'-dithiodipyridine. In the Bence-Jones dimer from a second patient the interchain disulfide bond is reduced with dithiothreitol. A covalently linked hybrid molecule is produced by the reaction of the mixed disulfide with the reduced thiol. In favorable cases the mild treatment yields heterodimers which can be crystallized for X-ray diffraction studies. The procedure can also be employed for converting a monomer into a covalent dimer. The engineered dimer of one kappa chain (Jen) crystallizes in the same space group as an aggregate of monomers, but the unit cell is only one-third as large.

Bence Jones Protein↗
PubMed1987

Age-related retinal vasculopathy.

Second and third order retinal arterioles and venules were studied by immunohistochemistry and electron microscopy in the uncomplicated ageing process and in association with central retinal vascular occlusive disease (CRVOD). Tissue was obtained from eight enucleated human eyes (4 control, 4 with manifestations of CRVOD) and the investigation was directed towards abnormalities in the myocytes and the nature of collagenous materials which are deposited during the process of hyalinization. In normal ageing and in two cases of CRVOD, the endothelial cell monolayer and the underlying cells (subendothelial myocytes) were preserved in arterioles and venules: there was no evidence of fibrin leakage. Degenerative changes were found in the medial myocytes in control tissue from the fifth decade and these included myocyte shrinkage, accumulation of intracytoplasmic membranous structures, cytoplasmic vacuolation and fragmentation. The 'hyalinized' acellular vessel wall seen in CRVOD contains scattered activated fibroblast-like myocytes and macrophages lying within a matrix of fibronectin, 65 nm collagen and multilayered basement membrane material. Endothelial cells and cohort subendothelial myocytes are involved in the formation of capillaries which bud into the hyalinized vessel wall in CRVOD. In two cases of CRVOD there was extensive cellular degeneration and cell debris accumulated within the degenerate stroma: this was attributed to superadded total ischaemia. The pathogenesis of hyalinization remains obscure but a subtle age-related dysfunction of the morphologically intact lining endothelium could be responsible for metabolic damage to myocytes in the media.

Aged↗
PubMed1987

Electrophoretic and immunological analysis of human glutathione S-transferase isozymes.

Several electrophoretically distinct glutathione S-transferase isozymes from different tissues have been purified and characterized. The data confirm the suggestion that GST-1, GST-2 and GST-3 are the products of separate genetic loci. An apparently muscle-specific isozyme termed GST-4 has been identified and shown to differ structurally from GST-1, GST-2 and GST-3. It is likely that GST-4 is the product of an additional gene locus. Two isozymes termed GST-5 and GST-6 were purified from brain. GST-5 has a different isoelectric point, but shares many structural features with GST-1. GST-5 may be a brain-specific post-translationally modified product of the GST-1 gene. GST-6 is an acidic isozyme found in many tissues. The data indicate that GST-6 is composed of two dissimilar subunits that do not cross-react with antiserum directed against GST-1, GST-2 or GST-3. These observations therefore suggest that GST-6 may have an independent genetic origin.

Amino Acid Sequence↗
PubMed1985

Identification of a common antigen on human erythrocyte sialoglycoproteins.

An erythrocyte sialoglycoprotein common antigen has been identified by a monoclonal antibody. The antigen recognised by the JCS-2 antibody was determined by immunoprecipitation, Western blotting and partial amino acid sequencing. Western blot analysis of human erythrocyte ghost membranes separated on sodium dodecyl sulphate polyacrylamide gel electrophoresis shows that the sialoglycoprotein common antigen occurs on the alpha, beta, gamma and delta sialoglycoproteins, either in their monomeric or dimeric form and as the heterodimer in the case of alpha and delta. The N-terminal sequence of the antigen prepared by immunoaffinity chromatography of the Triton-X100 extract of human erythrocyte ghosts shows the first 9 residues to be identical to the known sequence of the MN blood group glycoproteins. The common epitope on the sialoglycoproteins resides on the oligosaccharide and contains sialic acid.

Antibodies, Monoclonal↗
PubMed1985

The amino acid sequence of equine milk lysozyme.

The amino acid sequence of equine milk lysozyme has been elucidated. The study involves the determination of the sequence of the N-terminal region of the whole protein, cyanogen bromide fragments, tryptic and chymotryptic peptides and fragments produced by chemical cleavage after tryptophan residues. The protein consists of a single chain of 129 amino acid residues and has a Mr of 14647. While equine milk lysozyme has the essential features of a c(chick)-type lysozyme, there is only 51% sequence homology with human milk lysozyme and 50% with domestic hen egg white lysozyme. Some of the implications of the large number of differences are discussed.

Amino Acid Sequence↗
PubMed1984

Comparison of bovine serum transferrin A and D2. I. Amino acid residue differences.

A comparison is made of single components of the homozygous variants A and D2 of bovine serum transferrin by tryptic, chymotryptic and cyanogen bromide digestion. It is concluded that there are three substitutions A:D2-Glu:Asp, Lys:Arg and Asp:Gly. In the light of the recent work of Brock et al. (1980) it is concluded that all three substitutions occur in the C-terminal sequence of the chain. By homology with the sequence of human serum transferrin (MacGillivray et al., 1982) the Lys:Arg and Asp:Gly substitutions probably occur at residues 527 and 446, respectively, from the N-terminus. The Asp:Gly substitution is considered more likely than our earlier conclusion (Maeda, McKenzie & Shaw, 1977) that there is a deletion in the chain of D2 (A:D2, Asp:--). The location of the Glu:Asp substitution is not known.

Amino Acid Sequence↗
PubMed1984

Comparison of bovine serum transferrin A and D2. II. Glycopeptides.

Glycopeptides are isolated from subtilisin and pronase digests of whole bovine serum transferrin A and D2. The two variants yield glycopeptides with identical amino acid composition. Hence, there is probably no amino acid substitution in this region of the peptide chain. Amino acid sequence determination of one glycopeptide (subtilisin glycopeptide 8) gives the sequence: (CHO)Asn-Ser-Ser-Leu-Cys. This sequence is identical with that of residues 491-495 of the sequence for human serum transferrin (MacGillivray et al., 1982) except that in the bovine transferrin, Asp is replaced by Asn, enabling carbohydrate attachment. A second glycopeptide sequence Arg-(CHO)Asn-Ala-Thr-Tyr is observed, and the significance discussed in relation to carbohydrate moieties of serum glycoproteins.

Amino Acid Sequence↗
PubMed1984

Structural gene for the phosphate-repressible phosphate-binding protein of Escherichia coli has its own promoter: complete nucleotide sequence of the phoS gene.

The complete nucleotide sequence of the phoS gene, the structural gene for the phosphate-repressible, periplasmic phosphate-binding protein Escherichia coli K-12, was determined. The phosphate-binding protein is synthesized in a precursor form which includes an additional N-terminal segment containing 25 amino acid residues, with the general characteristics of a signal sequence. The amino acid sequence derived from the nucleotide sequence shows the mature protein to be composed of 321 amino acids with a calculated molecular weight of 34,427. The phoS gene is not part of an operon and is transcribed counterclockwise with respect to the E. coli genetic map. A promoter region has been identified on the basis of homology with the consensus sequence of other E. coli promoter regions. However, an alternative promoter region has been identified on the basis of homology with the promoter regions of the phoA and phoE genes, the structural genes for alkaline phosphatase and outer-membrane pore protein e, respectively.

Amino Acid Sequence↗
PubMed1984

Principles and techniques of splinting musculocutaneous injuries.

Splinting should be used as soon after a musculoskeletal injury as possible, and the splint should be maintained (in some form) until the injury is healed to the extent that protected limb function can be resumed without pain. This principle is the overriding guide to the appropriate pre-hospital management of these injuries. In the emergency department, the physician performs a careful physical examination, without removing the splint if possible, and takes the patient's history in order to arrive at an accurate diagnosis before the splinted patient is sent for x-ray evaluation.

Adult↗
PubMed1984

The amino acid sequence of equine alpha-lactalbumin.

The amino acid sequence of equine alpha-lactalbumin has been determined with the aid of an automatic sequencer. The protein chain consists of 123 amino acids and has a Mr of 14218. Elucidation of the structure involved sequence determination of native protein (residues 1-32), cyanogen bromide fragments, and tryptic, chymotryptic and S. aureus V8 proteolytic peptides. Approximately 67% of the residues are identical with corresponding residues of bovine alpha-lactalbumin B, and there is close homology with alpha-lactalbumin of other species.

Amino Acid Sequence↗
PubMed1983

A chemical and enzymological comparison of the common major human erythrocyte carbonic anhydrase II, its minor component, and a new genetic variant, CA II Melbourne (237 Pro leads to His).

A new variant of human erythrocyte carbonic anhydrase II (CA II) was discovered in a single Caucasian family during routine screening of blood samples from Melbourne, Australia. The normal and variant enzymes in the heterozygous CA II mixture, as well as a minor component of the normal enzyme, were resolved by isoelectric focusing following purification by a specific affinity matrix. Specific esterase activities of all three were very similar, but quite different Michaelis-Menten constants were noted for the minor component. No differences were noted with respect to inhibition by acetazolamide, but the minor component was more sensitive to chloride inhibition. Double diffusion analysis showed the immunological identity of the normal, variant, and minor components. Both the variant CA II and the minor component were less heat stable than the normal enzyme, but all forms showed identical rates of inactivation upon dialysis against the zinc chelator pyridine dicarboxylic acid. Amino acid analyses of the whole protein and the single difference peptide were consistent with a proline to histidine substitution in the variant. This was identified as 237 Pro leads to His by a process of elimination involving direct sequencing of tryptic and cyanogen bromide peptides. The numbering is by homology with the human CA I sequence.

Adult↗
PubMed1983

Comparison of adenylate kinase from normal and malignant hyperpyrexic porcine muscle.

Adenylate kinase has been implicated as a key factor in malignant hyperpyrexia, a complication of general anaesthesia which is usually triggered by the anaesthetic drug, halothane. Because of this, the enzyme was purified from both malignant hyperpyrexia susceptible and control porcine muscle. Electrophoretic studies, amino acid analysis, and peptide mapping of the purified enzymes revealed no significant differences between the two preparations. Both enzymes responded similarly to halothane and to the three sulfhydryl reacting reagents which were tested and they also showed an identical affinity for the substrate AMP. It is concluded that porcine MH is not due to an abnormality in the enzyme AK.

Adenylate Kinase↗
PubMed1983

Determination of the amino acid substitution in human prothrombin type 3 (157 Glu leads to Lys) and the localization of a third thrombin cleavage site.

Prothrombin was purified from normal blood donors and individuals heterozygous for prothrombin type 3. Comparison of the purified prothrombin preparations by tryptic peptide mapping, amino acid analysis and automated sequencing after thrombin digestion, has indicated that prothrombin type 3 results from the substitution of a lysine residue for glutamic acid at position 157. This substitution can result from a single base change in the structural gene and explains the relatively slow electrophoretic mobility of prothrombin type 3 at alkaline pH. An additional thrombin cleavage site in profragment 1 has been identified at arginine 54 by automated sequence analysis of thrombin digests by prothrombin.

Amino Acid Sequence↗
PubMed1982

Purification, properties, partial sequence and evolutionary relationships of marsupial erythrocyte carbonic anhydrase.

Carbonic anhydrase (EC 4.2.1.1) has been purified from the erythrocytes of the tammar wallaby (Macropus eugenii desmarest). The enzyme was separated into four zones of activity. The three major individual forms were isolated as discrete entities. Comparison of substrate specificity, specific activities, kinetic constants and inhibition characteristics indicated that these heteromorphs represented minor post-translational modifications of a single gene product of carbonic anhydrase II type. Double-immunodiffusion and peptide mapping confirmed this proposition. The marsupial enzyme exists as a monomer with a molecular weight of about 29 000 containing one atom of zinc per mole which is much more tightly bound to the enzyme than it is in either human carbonic anhydrase I or II. The wallaby enzyme was, like human carbonic anhydrase II, partially inactivated by p-hydroxymercuribenzoate under conditions not inhibitory for human carbonic anhydrase I. The partial sequence of 51 residues of cyanogen-bromide peptides was sufficiently homologous to allow unambiguous overlap with the sequence of both human carbonic anhydrase I and II isozymes as well as with the recently published sequence of an apparent type I-like enzyme from the turtle. It is clear that the single wallaby erythrocyte carbonic anhydrase belongs to the class of separately evolving type II isozymes which have previously been defined only for placental mammals.

Acetazolamide↗
PubMed1982

Physicochemical characterization of lens proteins of the squid Nototodarus gouldi and comparison with vertebrate crystallins.

The main water-soluble proteins of squid lens (S-crystallins) have a molecular weight of 60 000, a sedimentation coefficient s020,w of 5.2 S, 20-30% alpha-helical secondary structure, and an unusually high methionine content (12%). The subunits of Mr 30 000 (major) and Mr 27 000 (minor) have related N-terminal amino acid sequences, but a very heterogeneous charge distribution with predominantly basic isoelectric points. Higher-Mr aggregates have similar secondary/tertiary structure and amino acid composition, but contain additional acidic subunits and Mr 35 000-40 000 subunits. S-crystallins resemble vertebrate beta-crystallins in their quaternary structure, and their N-terminal sequence shows analogy with the first 19 residues of calf beta/gamma-crystallin folding units. In the urea-soluble and urea-insoluble lens fractions polypeptides of Mr 58 000 and 80 000, respectively, predominate, which presumably correspond to the main cytoskeleton and membrane proteins. Water-soluble lens components of less than Mr 2000 were isolated which have ultraviolet absorption maxima at 327 and 370 nm.

Animals↗
PubMed1982

A polymorphic variant of human erythrocyte carbonic anhydrase I with a widespread distribution in Australian aborigines, CAI Australia-9 (8 Asp leads to Gly): purification, properties, amino acid substitution, and possible physiological significance of the variant enzyme.

Carbonic anhydrase I (EC 4.2.1.1) purified from the pooled packed red blood cells of 100 individuals typed as heterozygous for the common Australian Aboriginal carbonic anhydrase I variant CAI Australia-9 had a slightly higher specific CO2 hydratase or esterase (toward p-nitrophenyl acetate) activity than the normal component and a higher Km and Vmax using the esterase substrate. The variant enzyme was slightly more resistant to heat inactivation. The extent of inhibition of both enzymes by the specific inhibitor acetazolamide was identical, as was their immunological behavior and the lability of the active-site zinc ion. The variant enzyme was more resistant to chloride inhibition. The physiological importance of this observation is discussed in the context of a proposed adaptive advantage of the variant gene in the arid western and central regions of Australia. The amino acid substitution in the Aboriginal variant of a glycine for an aspartic acid residue has been located at residue 8 from the N terminus (i.e., 8 Asp leads to Gly), by proteolytic and partial acid hydrolyses. The possible effects of this substitution on the structure and function of the molecule are discussed.

Amino Acid Sequence↗
PubMed1982

Chemical and enzymological characterization of an Indonesian variant of human erythrocyte carbonic anhydrase II, CAII Jogjakarta (17 Lys leads to Glu).

A new variant of human erythrocyte carbonic anhydrase II (CAII) was discovered in a single heterozygous individual during routine screening of blood samples from the island of Java in Indonesia. The normal and variant components of the heterozygous CAII mixture were resolved by isoelectric focusing following purification by a specific affinity matrix. Specific esterase activities and Michaelis-Menten constants were identical. Only very small differences were noted with respect to inhibition by acetazolamide and chloride. Double diffusion analysis showed the immunological identify of the normal and variant enzymes. The variant CAII was considerably less heat stable than the normal enzyme. The variant was slightly more stable than the normal enzyme upon dialysis against the zinc chelator dipicolinic acid (PDCA), indicating a tighter binding of zinc than the normal enzyme. Analysis of tryptic peptides from the normal and variant enzymes indicated that, in the variant, lysine at position 17 from the N terminus had changed to glutamic acid. The differences in physiochemical properties observed for the normal and variant enzyme are discussed in relation to the possible effects of this substitution on the structure of the CAII molecule.

Amino Acid Sequence↗