Inhibition of brain tubulinyl-tyrosine carboxypeptidase by endogenous proteins

✍ Scribed by N. M. Modesti; C. E. Argaraña; H. S. Barra; Dr. R. Caputto

• Book ID: 102909485
• Publisher: John Wiley and Sons
• Year: 1984
• Tongue: English
• Weight: 652 KB
• Volume: 12
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.490120407

✦ Synopsis

When a 25-50 % ammonium-sulphate-insoluble fraction from a bovine brain preparation was chromatographed on a cellulose phosphate column, several protein fractions which inhibit the activity of tubulinyl-tyrosine carboxypeptidase were obtained. One of these fractions exhibited activity of fructose-bisphosphate aldolase (EC 4.1.2.13) and the enzyme accounted for more than 95% of the protein of this fraction as judged by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The inhibitory activities of the two protein fractions which had the highest activity per mg of protein were practically abolished by pretreatment with pronase; preincubation with trypsin, on the other hand, caused only a partial inactivation of the inhibitors. The inhibitory activities were little affected by heating at 90°C for 5 min. Preincubation with purified tubulinyl-tyrosine carboxypeptidase caused a great decrease of the inhibitory activities of these two fractions, leaving open the possibility that these inhibitors act as substrates of the carboxypeptidase.