Purification and partial characterization of the soluble low Km 5'-nucleotidase from human seminal plasma.
Biochim Biophys Acta
; 1080(3): 252-8, 1991 Nov 15.
Article
en En
| MEDLINE
| ID: mdl-1954233
ABSTRACT
Soluble low Km 5'-nucleotidase from human seminal plasma has been purified to homogeneity by one affinity and two gel-filtration chromatographic steps. The pure enzyme had a specific activity of 2000 nmol min-1 mg-1. Sodium dodecyl sulphate polyacrylamide gel electrophoresis of purified low Km 5'-nucleotidase revealed a single polypeptide band of 40 +/- 7 kDa and a tetrameric structure of 160 +/- 10 kDa has been proposed for the native enzyme. The kinetic properties of low Km 5'-nucleotidase have been determined and rather unique characteristics have been found for this soluble low Km 5'-nucleotidase the substrate efficiency was slightly higher for IMP with an optimum pH at 7.5; the enzyme showed an absolute dependence on Mg2+ ions. Ca2+ could replace Mg2+ ions for activity while other divalent cations could not substitute for Mg2+; the enzymes were equally activated by ATP and ADP up to 0.1 mM concentrations. At higher concentrations up to 1 mM, ADP was still an activator while ATP caused a gradual decrease of activation to the native activity. This effect could not be related to the Mg-ATP = complexes since the enzymic preparation Mg(2+)-free still showed the same biphasic pattern of activation.
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Banco de datos:
MEDLINE
Asunto principal:
Semen
/
5'-Nucleotidasa
Límite:
Humans
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
1991
Tipo del documento:
Article
País de afiliación:
Italia