Cloning and characterization of two Lactobacillus casei genes encoding a cystathionine lyase.
Appl Environ Microbiol
; 74(1): 99-106, 2008 Jan.
Article
em En
| MEDLINE
| ID: mdl-17993563
ABSTRACT
Volatile sulfur compounds are key flavor compounds in several cheese types. To better understand the metabolism of sulfur-containing amino acids, which certainly plays a key role in the release of volatile sulfur compounds, we searched the genome database of Lactobacillus casei ATCC 334 for genes encoding putative homologs of enzymes known to degrade cysteine, cystathionine, and methionine. The search revealed that L. casei possesses two genes that putatively encode a cystathionine beta-lyase (CBL; EC 4.4.1.8). The enzyme has been implicated in the degradation of not only cystathionine but also cysteine and methionine. Recombinant CBL proteins catalyzed the degradation of L-cystathionine, O-succinyl-L-homoserine, L-cysteine, L-serine, and L-methionine to form alpha-keto acid, hydrogen sulfide, or methanethiol. The two enzymes showed notable differences in substrate specificity and pH optimum.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cistationina
/
Lacticaseibacillus casei
/
Liases
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article