Kinetics and inhibition studies of catechol O-methyltransferase from the yeast Candida tropicalis.
AUTOR(ES)
Veser, J
RESUMO
The Kms for esculetin and S-adenosyl-L-methionine for catechol O-methyltransferase from the yeast Candida tropicalis were 6.2 and 40 microM, respectively. S-Adenosyl-L-homocysteine was a very potent competitive inhibitor with respect to S-adenosyl-L-methionine, with a Ki of 6.9 microM. Of the catechol-related inhibitors, purpurogallin, with a Ki of 0.07 microM, showed the greatest inhibitory effect. Sulfhydryl group-blocking reagents, such as thiol-oxidizing 2-iodosobenzoic acid and mercaptide-forming p-chloromercuribenzoic acid, provided evidence for sulfhydryl groups in the active site of the enzyme. Yeast catechol O-methyltransferase is a metal-dependent enzyme and requires Mg2+ for full activity. Zn2+ and Mn2+ but not Ca2+ were able to substitute for Mg2+. Mn2+ showed optimal enzyme activation at concentrations 50- to 100-fold lower than those of Mg2+.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=212453Documentos Relacionados
- Purification and Characterization of Streptomyces griseus Catechol O-Methyltransferase
- Catechol O-methyltransferase val158-met genotype and individual variation in the brain response to amphetamine
- Development of an integrative DNA transformation system for the yeast Candida tropicalis.
- Purification and Properties of an S-Adenosylmethionine: 2,4-Disubstituted Phenol O-Methyltransferase from Phanerochaete chrysosporium
- Biosynthesis of Puromycin in Streptomyces alboniger: Regulation and Properties of O-Demethylpuromycin O-Methyltransferase
