PubMed Health⌕ Search

Biomedical subjects

J L Strominger

Publications and source records attributed to J L Strominger.

At least 541 records · Page 30Linked to original sources
PubMed1974

Heterogeneity of HL-A antigen preparations is due to variable sialic acid content.

Purified, papain-solubilized preparations of HL-A antigen from cultured human lymphoblastoid cells (HL-A2 and HL-A7,12 from RPMI 4265 cells and a mixture of HL-A3, W-25, HL-A12, and HL-A27 from IM-1 cells) show substantial charge heterogeneity in isoelectric focusing gels. This heterogeneity can be ascribed largely to variable numbers of sialic acid residues on each molecule. Neuraminidase (EC 3.2.1.18) treatment of the HL-A antigens as a function of time altered the band patterns in a manner demonstrating that up to three sialic acid residues are present on both first locus ("LA") and second locus ("Four") antigens. Neuraminidase treatment did not alter the specificity or specific activity of the purified antigens.

Animals↗
PubMed1974

Enzymatic utilization of P1-di-N-acetylchitobiosyl P2-dolichyl pyrophosphate and its chemical synthesis.

Fully acetylated chitobiose was treated with phosphoric acid to give a mixture of products from which 2-acetamido-4-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta- D-glucopyranosyl)-3,6-di-O-acetyl-2-deoxy-alpha,beta- D-glucopyranosyl phosphate (Ac(3)GlcNAc-Ac(2)GlcNAc-P) was isolated by preparative thin layer chromatography. Treatment of this compound with P(1)-diphenyl P(2)-dolichyl pyrophosphate gave an acetylated pyrophosphate diester, which was purified chromatographically and deacetylated. The product, P(1)-di-N-acetylchitobiosyl P(2)-dolichyl pyrophosphate (Dol-P-P-GlcNAc-GlcNAc), was readily separated from P(1)-2-acetamido-2-deoxy-alpha-D-glucopyranosyl P(2)-dolichyl pyrophosphate (Dol-P-P-GlcNAc) by thin layer chromatography in several solvent systems. Addition of this compound to human lymphocyte membrane preparations led to the formation of a mannose-containing derivative which appears to be an oligosaccharide phospholipid, as judged by its behavior on DEAE-cellulose chromatography and by its hydrolysis to give an oligosaccharide containing more than four monosaccharide units.

Cell Membrane↗
PubMed1974

Partial purification of detergent-soluble HL-A antigen and its cleavage by papain.

HL-A antigen solubilized with the non-ionic detergent, Brij 99, has been purified to about 50% of homogeneity from a cultured human lymphoblast line. It consists of two nonidentical subunits of 44,000 and 12,000 molecular weight (MW). Upon papain proteolysis the 44,000 MW peptide is converted by at least two cleavages to a 34,000 MW peptide, but the 12,000 MW peptide appears to be unchanged. Concomitantly, the apparent molecular weight in gel filtration chromatography under nondenaturing conditions in the presence of Brij 99 is reduced from 460,000 to 45,000. HL-A molecules produced by direct papain proteolysis of membranes and by papain treatment of purified detergent-soluble HL-A are identical.

Animals↗
PubMed1974

Immunological identity of the small subunit of HL-A antigens and beta2-microglobulin and its turnover on the cell membrane.

A number of immunological methods have been employed to show that the small subunit of HL-A antigens, isolated either after papain treatment or after solubilization with detergent, is identical to beta(2)-microglobulin, a protein previously isolated from human urine and shown to be homologous in structure to constant region domains of immunoglobulins. Moreover, quantitative data indicate virtually total identity between the small subunit of HL-A antigens and beta(2)-microglobulin. Studies of the turnover of labeled HL-A antigens from the lymphocyte surface indicate that the two subunits turn over at similar rates, although only the small subunit could be detected in the culture medium. The significance of these observations is discussed.

Animals↗