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URIDINE PHOSPHORYLASE FROM RAT BRAIN: CHARACTERISTICS AND DEVELOPMENTAL COURSE
Author(s) -
Guroff G.,
Rhoads Carol A.
Publication year - 1969
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.1471-4159.1969.tb09910.x
Subject(s) - uridine , enzyme , cytidine , nucleotide salvage , biochemistry , deoxyuridine , enzyme assay , chemistry , thymidine , thymidine phosphorylase , specific activity , biology , rna , nucleotide , dna , gene
—Uridine phosphorylase (uridine: orthophosphate ribosyltransferase; EC 2.4.2.3) from rat brain was purified and its properties were studied. The enzyme resembled preparations made from other mammalian sources. Its pH optimum was between 7·6 and 8·0. An examination of its action on various substrates showed rates of reaction in the order: uridine > deoxyuridine > thymidine > cytidine. The enzyme showed a requirement for phosphate which could also be satisfied by arsenate. The activity of the enzyme was protected from heat inactivation by uridine and by phosphate. In brain and liver the activity of the enzyme increased five‐ to ten‐fold between 10 and 20 days of life. Injections of cortisol or of uridine did not increase the enzymic activity.