PubMed Health⌕ Search

Biomedical subjects

H Anundi

Publications and source records attributed to H Anundi.

11 recordsLinked to original sources
PubMed1991

Identification of human blood plasma and serum proteins in two-dimensional gels by use of protein A-Sepharose: application to alpha 1-microglobulin.

The relative position identification of some of the proteins in human blood plasma and serum after separation by two-dimensional electrophoresis (2-DE) in gel slabs have been studied. Antibodies specific to the protein to be identified were first immobilized on Protein A-Sepharose. Serum or plasma samples devoid of this protein were obtained following adsorption and subsequently the protein itself was eluted. The preparations were examined by 2-DE, silverstaining and blotting with parallel analysis of the purified proteins. Position identification in 2-DE gels of the spots of alpha 1-microglobulin (= protein HC) is shown as an example. The technique has general applicability not only for identification of the positions in 2-DE gels of serum and plasma proteins but also for proteins in other fluids, tissues and organs from humans and other species.

Alpha-Globulins↗
PubMed1987

The complete amino acid sequence of human serum retinol-binding protein.

The complete amino acid sequence of human serum Retinol-binding protein (RBP) including the distribution of its three disulfide bridges, has been determined. The protein consists of 182 amino acid residues, the order of which was determined following the isolation of five CNBr-fragments. Direct amino acid sequence analysis in an automatic liquid phase sequencer provided almost the entire sequences of the five CNBr-fragments. Several sets of enzymatically derived peptides of RBP were also used to elucidate the primary structure. RBP displays significant homology to bovine beta-lactoglobulin, human alpha 1-microglobulin and rat alpha 1-microglobulin. RBP contains an internal homology. Thus, residues 36 to 83 display statistically significant homology with residues 96 to 141.

Alpha-Globulins↗
PubMed1985

Amino acid sequence homologies between rabbit, rat, and human serum retinol-binding proteins.

The main transporting protein for vitamin A in rabbit serum, the retinol-binding protein (RBP), was isolated and its amino acid sequence determined. Rabbit RBP was found to be highly homologous to human RBP, whose amino acid sequence was elucidated earlier, and to rat RBP. The rat RBP sequence was obtained by combining information deduced from the nucleotide sequences of two overlapping cDNA clones with the NH2-terminal sequence of the isolated protein determined by automated Edman degradation. The identity between the three proteins is approximately 90%. The high degree of homology between RBP molecules from different species is probably explained by the fact that RBP participates in at least three types of molecular interactions: in the binding of prealbumin, in the interaction with retinol, and in the recognition of a specific cell surface receptor. All these interactions should lead to a conservation of RBP structure. The amino acid differences between rabbit, rat, and human RBP are discussed in light of the recent elucidation of the three-dimensional structure of human RBP. Hybridization of a probe isolated from a rat RBP cDNA clone to restriction enzyme-digested genomic DNA from rat and mouse suggests that RBP is encoded by a single gene.

Amino Acid Sequence↗
PubMed1985

The primary structure of rat liver cellular retinol-binding protein.

The complete amino acid sequence of a cellular retinol-binding protein (CRBP) has been determined for the first time. The primary structure of rat liver CRBP was elucidated by analyses of cyanogen bromide fragments and peptides obtained by tryptic and thermolytic digestions. The single polypeptide chain of rat CRBP consists of 134 amino acid residues. Under reducing conditions, CRBP exists as a monomer, but, in the absence of reducing agents, dimers and multimers of the protein emerge. This is explained by the observation that CRBP contains 3 cysteines, one of which seems to be highly reactive. Whether CRBP contains a disulfide bond is not yet established. The present data extend the previously described homology between CRBP and a family of low molecular weight proteins, all members of which may bind hydrophobic ligands. Since some of these proteins apparently display intracellular transport functions, a similar role for CRBP is envisaged.

Amino Acid Sequence↗
PubMed1975

The subunit structure of thymus leukemia antigens.

EDTA-containing buffer solubilizes thymus leukemia antigens (TLa) from crude thymocyte membrane fractions. The TL antigens consist mainly of molecules of a size similar to immunoglobulin G when gel chromatography analyses were performed under physiological conditions. A single component of TLa was apparent on sucrose density gradient ultracentrifugation of solubilized thymocyte membrane macromolecules as monitored by indirect immunoprecipitation. The sedimentation constant for the TL antigens (5.8 S) was considerably less than that for immunoglobulin G. The gel chromatography and ultracentrifugation data suggest an apparent molecular weight for TLa of about 120000. TLa isolated by indirect immunoprecipitation is composed of two types of polypeptide chains. The smaller subunit was identified as beta2-microglobulin. The larger polypeptide chain carried the alloantigenic determinants and displayed a molecular weight of about 50000 after reduction and alkylation. TLa subjected to molecular weight determination under denaturing conditions was composed of two components. The smaller component was beta2-microglobulin which evidently is linked to the larger polypeptide chain by noncovalent interactions only. The larger component had a size greater than reduced and alkylated immunoglobulin G heavy chains. Upon reduction and alkylation of the latter component its size was reduced and it appeared to have a molecular weight of about 50000. Consequently, TLa is composed of two disulfide linked heavy polypeptide chains and two beta2-microglobulin molecules. TLa solubilized by papain digestion comprises two polypeptide chains, one of which is beta2-microglobulin. The larger 37000-dalton subunit is a fragment of the heavy polypeptide chain. This was demonstrated by digesting solubilized 120000-dalton TLa with papain. The proteolytic fragments obtained were indistinguishable from those directly released from the cell surface by proteolysis. The papain-derived TLa fragment exhibited most if not all the alloantigenic determinants.

Animals↗
PubMed1975

Evolutionary relationship between immunoglobulins and transplantation antigens.

The major human and murine histocompatibility antigens are tetrameric molecules with an apparent molecular weight of about 130,000. They are composed of two types of polypeptide chains. The two light chains, previously identified as beta2-microglobulins, are bound to the two heavy, alloantigenic HL-A or H-2 polypeptide chains by noncovalent interactions only. The heavy chains are held together by disulfide bridge(s) located in the part of the molecule that is attached to the cell membrane. By limited proteolysis of the histocompatibility antigens evidence was obtained suggesting that the heavy chain may consist of three compact domains connected by more extended stretches of polypeptide chain. Each domain appeared to contain a single disulfide bride encompassing about 60 to 70 amino-acid residues. Staphylococcus aureus protein A is known to bind exclusively to the Fe region of immunoglobulin G. It was, however, observed that protein A interacts in a similar way with the H-2 antigen heavy chain. This observation, together withthe homology of the primary structure of beta2-microglobulin to immunoglobulin G, the tetrameric structure of the alloantigens, the ogranizations of the heavy polypeptide chain into compact domains, and the presence of a single, immunoglobulin-like disulfide loop in each domain, establishes a close similarity in structure between histocompatibility antigens and immunoglobulins. The similarity in structural features suggests a common evolutionary origin of the two types of molecules.

Animals↗
PubMedDate not supplied

High performance concentration and gel filtration of rat urinary protein allergens.

Allergies to laboratory animals, notably rats, have become an increasingly recognized occupational problem. Identification and isolation of the individual proteins causing allergic reactions, could form the basis for early recognition of sensitivity, diagnosis, control of degree of pollution of the environment and desensibilization treatments. Frequently, allergens originate from dried rat urine. Because earlier published methods were found unsatisfactory we have developed a new strategy for isolation of rat urinary proteins including a high performance technique for their mild concentration on hydroxyapatite. The concentrated allergens have been fractionated according to molecular size by high performance gel filtration and according to carbohydrate content by wheat germ lectin-Sepharose 6 MB affinity chromatography. The obtained fractions have been examined by denaturing and non-denaturing polyacrylamide gradient gel electrophoresis followed by sensitive staining procedures, and tested with respect to allergenicity by skin tests on allergic patients.

Adult↗