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Biomedical subjects

M B Mathews

Publications and source records attributed to M B Mathews.

At least 163 records · Page 9Linked to original sources
PubMed1973

Mucopolysaccharides: comparison of chondroitin sulfate conformations with those of related polyanions.

X-ray diffraction shows that chondroitin 6-sulfate, and some further rulfated derivatives, can occur in two ordered structures in stretched films. Both structures contain single helices with similar projected disaccharide lengths (9.6 and 9.8 angstroms) but with very different turn angles between successive disaccharides (120 and 45 degrees). In contrast, coaxial double helices of hyaluronates and t-carrageenates have shorter projected disaccharide lengths (8.5 and 8.9 angstroms).

Carrageenan↗
PubMed1973

Double-stranded RNA as an inhibitor of protein synthesis and as a substrate for a nuclease in extracts of Krebs II ascites cells.

Concentrations of double-stranded RNA above about 0.1 mug/ml inhibit translation of encephalo-myocarditis viral RNA and mouse globin messenger RNA in extracts of Krebs II ascites cells. Protein synthesis initially proceeds at the control rate, then abruptly shuts off in a manner similar to that observed in reticulocyte lysates [Hunt, T. & Ehrenfeld, E. (1971) Nature New Biol. 230, 91-94]. Substantially higher concentrations of double-stranded RNA are required to give this effect in ascites extracts. Subcellular fractions of Krebs II ascites cells contain a nucleolytic activity capable of digesting several natural and synthetic double-stranded RNAs. This nuclease is most active under conditions of protein synthesis, and part of the activity remains associated with ribosomes upon sedimentation. It is probably because of digestion of double-stranded RNA by this nuclease that higher concentrations of double-stranded RNA are required for inhibition of protein synthesis in Krebs cell extracts than in reticulocyte lysates.

Animals↗
PubMed1971

Comparative biochemistry of chondroitin sulphate-proteins of cartilage and notochord.

Fragments that consisted mainly of two polysaccharide chains joined by a short polypeptide bridge (doublets) were prepared from chondroitin sulphate-proteins of lamprey, sturgeon, elasmobranch and ox connective tissues after hydrolysis with trypsin and chymotrypsin. Consideration of molecular parameters, compositions and behaviour on gel electrophoresis and density-gradient fractionation leads to a proposed parent structure for chondroitin sulphate-proteins. A single polypeptide chain of about 2000 amino acid residues contains alternating short and long repeating sequences. A short sequence consists of less than 10 amino acid residues with one N-terminal and one C-terminal serine residue, each of which carries a polysaccharide chain linked glycosidically to its hydroxyl group. This structure constitutes the doublet subunit. Some variation is introduced when the doublet subunit carries only a single polysaccharide chain. The long sequence contains about 35 amino acid residues and is subject to cleavage by trypsin and chymotrypsin. The main polypeptide is probably homologous in the vertebrate sub-phylum with strong conservation of structure suggested for the short sequence. However, polymorphism of polypeptide structures cannot be excluded.

Amino Acid Sequence↗