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Biomedical subjects

A M Blow

Publications and source records attributed to A M Blow.

8 recordsLinked to original sources
PubMed1979

Calcium ions and cell fusion. Effects of chemical fusogens on the permeability of erythrocytes to calcium and other ions.

1. Fusogenic and non-fusogenic chemicals were tesetd for their ability to allow 45Ca2+ and 3H2O to enter hen and human erythrocytes. 2. The ratio of 45Ca2+/3H2O in treated cells to that in untreated cells is referred to as the entry ratio. 3. Within 1 min at 37 degrees C both water-soluble and lipid-soluble fusogens increased the value of the entry ratio, which reached maximum values in 5--10 min. 4. Values of the entry ratio in the range of 4--12 were found under conditions that led to cell fusion. 5. Closely related but non-fusogenic chemicals did not significantly alter the entry ratio. 6. The entry ratios for 86Rb+, 22Na+ and 35SO42- were also significantly increased by both lipid-soluble and water-soluble fusogens, though the increases were not as large as those for 45Ca2+. 7. It is suggested that fusogenic compounds increase the permeability of biological membranes to ions, and that an increase in the concentration of intracellular Ca2+ initiates or facilitates events that lead to the chemically induced fusion of erythrocytes.

Animals↗
PubMed1977

Proteoglycan-degrading enzymes. A radiochemical assay method and the detection of a new enzyme cathepsin F.

1. Polyacrylamide beads containing entrapped 35S-labelled proteoglycan molecules have been prepared. 2. The measurement of release of radioactivity provides an extremely sensitive assay for proteoglycan-degrading enzymes, including proteinases and hyaluronidase. 3. The amount of label released is a logarithmic function of enzyme concentration or time of incubation. Experiments were made in an attempt to explain this. 4. Assays were made by the new method at several pH values, and with the inclusion of inhibitors to identify the proteoglycan-degrading enzymes of rabbit ear cartilage. 5. A previously undescribed proteinase active against proteoglycan at pH4.5 but unaffected by pepstatin, was discovered. The enzyme was named cathepsin F, and was partially purified and characterized; it was detected in human articular cartilage.

Acrylamides↗
PubMed1977

Action of human lysosomal elastase on the oxidized B chain of insulin.

The specificity of action of the lysosomal elastase of human neutrophil leucocytes on the oxidized B chain of insulin is similar to that of pig pancreatic elastase, but is more directed towards valine than alanine as the residue contributing the carboxyl group of the cleaved bond. The most susceptible bonds are Val-12-Glu-13 and Val-18-Cys(O3H)-19. Other bonds hydrolysed are Ala-14-Leu-15, Ser-9-His-10 and Cys, (O3H3)-7-Gly-8. Tables listing amino acid composition, N-terminal residue, and yields of isolated peptides have been deposited as Supplementary Publication SUP 50 075 (8 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1977) 161, 1.

Amino Acids↗
PubMed1977

Action of human cathepsin G on the oxidized B chain of insulin.

The specificity of cathepsin G, a serine neutral proteinase from human neutrophil leucotyes, was determine dby its action on the insulin B chain. The most susceptible bonds were Phe-24-Phe-25, Leu-15-Tyr-16 and Tyr-16-Leu-17. Other bonds hydrolysed were Leu-6-Cys(O3H)-7, Leu-11-Val-12, Leu-17-Val-18 and Phe-25-Tyr-26. These results suggest that the specificity of cathespin G is closer to that of pig chymotrypsin C than ox Chymotrypsin A. Tables listing amino acid composition, N-terminal residue, and yields of isolated peptides have been deposited as Supplementary Publication SUP 50 075 (8 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7B2, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1977) 161,1.

Amino Acids↗
PubMed1975

Metal-dependent proteinase of the lens. Assay, purification and properties of the bovine enzyme.

1. Two new assay methods were developed for the lens proteinase. In both, the substrate was alpha2-crystallin (a major lens protein); in the first method, the products were detected by reaction with trinitrobenzenesulphonate in the presence of SO32-, whereas in the second method, 3H-labelled substrate was used, and the products were detected as radioactivity soluble in trichloroacetic acid. 2. The neutral proteinase from bovine lens was partially purified by extraction of the lens at pH5.0 and column chromatography on hydroxyapatite and Sepharose 6B gel. 3. The purified enzyme had no detectable activity against haemoglobin, azo-casein or gamma-crystallin under optimum conditions for alpha2-crystallin. 4. The enzyme showed greatest activity and stability at pH7.5. It was reversibly inhibited by EDTA and 1,10-phenanthroline, and activated by Ca2+ and Mg2+. 5. Molecular weights obtained for the enzyme by chromatography on Sepharose 6B were approx. 500,000 in buffer of I = 0.02, and 250,000 at I = 1.02. 6. The properties of the purified lens proteinase are such as to suggest that this enzyme could account for the entire endopeptidase activity of the lens.

Animals↗