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CHANGES OF THYMIDINE KINASE IN THE DEVELOPING RAT BRAIN
Author(s) -
Yamagami S.,
Mow K.,
Kawakita Y.
Publication year - 1972
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1972.tb01346.x
Subject(s) - thymidine , thymidine kinase , cerebrum , cerebellum , enzyme , biochemistry , phosphotransferase , biology , specific activity , kinase , endocrinology , medicine , microbiology and biotechnology , immunology , in vitro , central nervous system , virus , herpes simplex virus
— Thymidine kinase (ATP: thymidine‐5′‐phosphotransferase EC 2.7.1.21) of the supernatant fraction from 6‐day‐old rat brain possessed a pH optimum of 8.0 and required the presence of 5mM‐ATP and 2.5 mM‐MgCl 2 for maximum activity. The activity was completely inhibited by addition of 1.8 mM‐TTP. The enzyme activity was lost if the same supernatant fraction was refrozen and thawed. K m was 2.8 × 10 −6 M for [6‐ 3 H]thymidine. Following subcellular fractionation of rat brain, the greatest proportion and highest specific activity of thymidine kinase was found in the supernatant fraction. Thymidine kinase activities reached a maximum at 6 days of age and then dropped sharply during maturation. Comparative studies of thymidine kinase activities of cerebrum, cerebellum and the remainder of the brain during growth indicated that the activity in the cerebellum was usually higher than those in the cerebrum and the remainder, and the biggest differences obtained at 6 days after birth corresponded with the peak in cerebellar activity.