Your browser doesn't support javascript.
loading
Overexpression and characterization of dimeric and tetrameric forms of recombinant serine hydroxymethyltransferase from Bacillus stearothermophilus.
J Biosci ; 2002 Jun; 27(3): 233-42
Artículo en Inglés | IMSEAR | ID: sea-110822
ABSTRACT
Serine hydroxymethyltransferase (SHMT), a pyridoxal-5' -phosphate (PLP) dependent enzyme catalyzes the interconversion of L-Ser and Gly using tetrahydrofolate as a substrate. The gene encoding for SHMT was amplified by PCR from genomic DNA of Bacillus stearothermophilus and the PCR product was cloned and overexpressed in Escherichia coli. The purified recombinant enzyme was isolated as a mixture of dimer (90%) and tetramer (10%). This is the first report demonstrating the existence of SHMT as a dimer and tetramer in the same organism. The specific activities at 37 C of the dimeric and tetrameric forms were 6 7 U/mg and 4 1 U/mg, respectively. The purified dimer was extremely thermostable with a T(m) of 85 degrees C in the presence of PLP and L-Ser. The temperature optimum of the dimer was 80 degrees C with a specific activity of 32 4 U/mg at this temperature. The enzyme catalyzed tetrahydrofolate-independent reactions at a slower rate compared to the tetrahydrofolate-dependent retro-aldol cleavage of L-Ser. The interaction with substrates and their analogues indicated that the orientation of PLP ring of B. stearothermophilus SHMT was probably different from sheep liver cytosolic recombinant SHMT (scSHMT).
Asunto(s)
Texto completo: Disponible Índice: IMSEAR (Asia Sudoriental) Asunto principal: Glicina Hidroximetiltransferasa / Temperatura / Geobacillus stearothermophilus / Estabilidad de Enzimas / Rastreo Diferencial de Calorimetría / Cinética / Catálisis / Expresión Génica / Reacción en Cadena de la Polimerasa / Cromatografía en Gel Idioma: Inglés Revista: J Biosci Año: 2002 Tipo del documento: Artículo

Similares

MEDLINE

...
LILACS

LIS

Texto completo: Disponible Índice: IMSEAR (Asia Sudoriental) Asunto principal: Glicina Hidroximetiltransferasa / Temperatura / Geobacillus stearothermophilus / Estabilidad de Enzimas / Rastreo Diferencial de Calorimetría / Cinética / Catálisis / Expresión Génica / Reacción en Cadena de la Polimerasa / Cromatografía en Gel Idioma: Inglés Revista: J Biosci Año: 2002 Tipo del documento: Artículo