Tubulinyl-tyrosine carboxypeptidase from chicken brain: properties and partial purification

ARGARAÑA CE; BARRA H.S,; CAPUTTO R.,

WILEY-BLACKWELL PUBLISHING, INC

Año: 1980 vol. 34 p. 114 - 114

yrosine can be released from tubulinyl-tyrosine by the action of a brain carboxypeptidase. The molecular weight of this enzyme found by gel filtration through a column of Sephadex G-200 was 90,000. The enzyme was very unstable in a purified preparation in which the activity per milligram of protein was increased 250-fold with respect to the starting material. The precise magnitude of the purification cannot be stated because of the unknown amount of endogenous tubulinyl-tyrosine in the material to be assayed. A comparative study was done between tubulinyl-tyrosine carboxypeptidase (TTCP) activity and pancreatic carboxypeptidase A (CPA, EC 3.4.12.2) activity using tubulinyl-[14C]tyrosine as substrate. The most remarkable differences found are: MgCl2 (2 mM), phenyl acetate (10 mM), or EDTA (5 mM) increased the TTCP activity whereas the CPA activity was strongly inhibited by these compounds. Iodoacetate (2 mM) and ZnCl2 (0.1 mM) inhibited the TTCP activity more than the CPA activity. Con