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R Zito

Publications and source records attributed to R Zito.

At least 37 records · Page 2Linked to original sources

The effects of acetylation on the binding region of cartilage proteoglycans to hyaluronic acid.

Proteoglycans in cartilage are found as aggregates and as monomers. Evidence has been obtained indicating that hyaluronic acid, normally present in this tissue, binds together monomers into large molecular weight aggregates. In this investigation, the interacting region of the protein backbone has been studied. The results unequivocally demonstrated that the epsilon amino groups of lysine are involved in hyaluronic acid binding to proteoglycans and that their blocking by acetylation either prevents reaggregation or disaggregates the high mol.w aggregates.

Acetylation↗

Purification and general properties of aspartate aminotransferase of ox heart.

1. A five-step procedure for preparing highly purified aspartate aminotransferase from ox heart is described. 2. The homogeneity of the pure enzyme was established by criteria such as ultracentrifugation and electrophoresis in starch gel and in polyacrylamide gel. 3. The pure enzyme has an isoelectric point of about pH5, and E(1%) (1cm.) 14.40 at 278mmu. 4. The molecular weight of the pure enzyme was determined as 96000 by sedimentation equilibrium. 5. The pH optimum for the pure enzyme was about 8. It was determined by a new assay technique. 6. A difference in the electrophoretic migration rate between the enzyme from ox heart and brain and the enzyme from pig heart and brain suggests a species specificity rather than an organ specificity. 7. A new effect of deionization on the visible-absorption spectrum of the enzyme was observed.

Animals↗

Amino acid composition and terminal residues of aspartate aminotransferase from ox heart.

1. The amino acid composition of highly purified aspartate aminotransferase from ox heart was determined. 2. Alanine is the only N-terminal residue. 3. Leucine was identified as the only C-terminal residue. 4. No disulphide bridges are present in the enzyme molecule. 5. The thiol groups are not equally accessible, the accessibility being comparatively easier in the apoenzyme molecule.

Amino Acids↗