D-glucosaminate aldolase activity of D-glucosaminate dehydratase from Pseudomonas fluorescens and its requirement for Mn2+ ion.
Biosci Biotechnol Biochem
; 59(3): 408-11, 1995 Mar.
Article
en En
| MEDLINE
| ID: mdl-7766176
When D-glucosaminate dehydratase (GADH) was incubated with D-glucosaminate (GlcNA) in veronal buffer (VB; 0.01 M, pH 8.0), GlcNA was converted stoichiometrically to glyceraldehyde, pyruvate, and ammonia (aldolase reaction A). This reaction occurred in addition to the dehydratase reaction (conversion of GlcNA to 2-keto-3-deoxy-D-gluconate and ammonia: alpha,beta-elimination reaction, B). The ratio of the activities (A:B) was about 1:4. However, in potassium phosphate buffer (KPB; 0.04 M, pH 8.0), the aldolase reaction was inhibited to 3-4% of that in VB, and also inhibited by various derivatives of glycerol, in particular, glycerol-3-phosphate (glycerol-3-P) and glyceraldehyde-3-phosphate (glyceraldehyde-3-P) in VB. The native enzyme was inhibited by incubation with 0.1 M EDTA, and the activity was restored by incubation of the EDTA-treated enzyme with (Mn2+ + pyridoxal 5'-phosphate (PLP)). When the EDTA-treated enzyme was incubated with (Mn2+ + PLP + glycerol-3-P), the activity of reaction B increased to 131% but that of reaction A decreased to 21%. These results suggested that Mn2+, PLP, and the phosphate group of glycerol-3-P are involved in formation of the active enzyme. In the case of the aldolase reaction, Mn2+ ion, which might be essential for the reaction, is chelated by the phosphate group of glycerol-3-P with resultant inhibition of the aldolase reaction.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Pseudomonas fluorescens
/
Aldehído-Liasas
/
Hidroliasas
/
Manganeso
Idioma:
En
Revista:
Biosci Biotechnol Biochem
Asunto de la revista:
BIOQUIMICA
/
BIOTECNOLOGIA
Año:
1995
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Reino Unido