Open AccessPurification and Some Properties of l ‐Glutamate Decarboxylase from Human Brain
Author(s) -
BLINDERMANN JeanMarc,
MAITRE Michel,
OSSOLA Lucienne,
MANDEL Paul
Publication year - 1978
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1978.tb12293.x
Subject(s) - glutamate decarboxylase , enzyme , polyacrylamide gel electrophoresis , chemistry , sodium , pyridoxal phosphate , glutamate receptor , biochemistry , gel electrophoresis , pyridoxal , amino acid , polyacrylamide , organic chemistry , receptor , cofactor , polymer chemistry
Glutamate decarboxylase (EC 4.1.1.15) from human brain has been purified 8000‐fold with respect to the initial homogenate. The molecular weight of the native enzyme was found to be 140000 by electrophoresis on a polyacrylamide gradient gel slab. The presence of a single protein band ( M r 67000) on sodium dodecylsulphate/polyacrylamide gel and the existence of only one N‐terminal amino acid suggest that the enzyme consists of two similar if not identical polypeptide chains. The K m of the enzyme at the optimum pH of 6.8 is about 1.3 × 10 −3 M for glutamate and 0.13 × 10 −6 M for pyridoxal phosphate. The analysis of the effects of various inhibitors of mouse brain glutamate decarboxylase on the human enzyme confirms the strong competitive inhibition caused by 3‐mercaptopropionic acid ( K i = 2.7 × 10 −6 M) while the K i values for allylglycine and chloride ion are 1.8 × 10 −2 M and 2.2 × 10 −2 M, respectively.