Site-directed mutagenesis of human brain GABA transaminase: lysine-357 is involved in cofactor binding at the active site.
Mol Cells
; 18(3): 314-9, 2004 Dec 31.
Article
en En
| MEDLINE
| ID: mdl-15650327
gamma-Aminobutyrate transaminase (GABA-T), a key enzyme of the GABA shunt, converts the major inhibitory neurotransmitter, GABA, to succinic semialdehyde. Although GABA-T is a pivotal factor implicated in the pathogenesis of various neurological disorders, its function remains to be elucidated. In an effort to clarify the structural and functional roles of specific lysyl residue in human brain GABA-T, we constructed human brain GABA-T mutants, in which the lysyl residue at position 357 was mutated to various amino acids including asparagine (K357N). The purified mutant GABA-T enzymes displayed neither catalytic activity nor absorption bands at 330 and 415 nm that are characteristic of pyridoxal-5'-phosphate (PLP) covalently linked to the protein. The wild type apoenzyme reconstituted with exogenous PLP had catalytic activity, while the mutant apoenzymes did not. These results indicate that lysine 357 is essential for catalytic function, and is involved in binding PLP at the active site.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Encéfalo
/
4-Aminobutirato Transaminasa
/
Lisina
Límite:
Humans
Idioma:
En
Revista:
Mol Cells
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
2004
Tipo del documento:
Article
Pais de publicación:
Corea del Sur