Open AccessBiosynthesis of 4‐Aminobutyrate aminotransferase
Author(s) -
CHOI SooYoung,
CHURCHICH Jorge E.
Publication year - 1986
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1986.tb10445.x
Subject(s) - biochemistry , reticulocyte , enzyme , biosynthesis , molecular mass , lysis , polyacrylamide gel electrophoresis , chemistry , pyridoxal , gel electrophoresis , cofactor , rna , biology , gene
Mitochondrial 4‐aminobutyrate aminotransferase was synthesized in a cell‐free reticulocyte lysate using polysomal RNA isolated from pig brain. Its primary translation product has a higher molecular mass than the mature enzyme. The difference in relative molecular mass is approximately 2000 as revealed by SDS/polyacrylamide gel electrophoresis. The precursor of 4‐aminobutyrate aminotransferase recognizes polyvalent antibodies raised against the mature enzyme. The precursor of 4‐aminobutyrate aminotransferase binds pyridoxal‐5‐ P and displays catalytic activity. Enzymatic activity was detected using a sensitive fluorimetric method, which is based on the formation of condensation products between succinic semialdehyde and cyclohexane‐1,3‐dione. It is concluded that removal of an extra peptid from the precursor is not an obligatory first step in the production of biological active species.