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Purification and Characterization of Bovine Brain 5′‐Nucleotidase
Author(s) -
Montero Josefa Mallol,
Fes Jorge Bozal
Publication year - 1982
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1982.tb11486.x
Subject(s) - 5' nucleotidase , chemistry , enzyme , imidazole , biochemistry , cytoplasm , nucleotidase , sodium , molecular mass , substrate (aquarium) , electrophoresis , adenosine , chromatography , biology , organic chemistry , ecology
The 5′‐nucleotidase located in the cytoplasmic fraction of bovine brain cortex was purified to electrophoretic homogeneity. The molecular weight was 134,000 daltons in the presence of sodium deoxycholate, whereas the enzyme formed high molecular weight aggregates in the absence of detergent. The purified enzyme showed the same kinetic and electrophoretic behaviour as the enzyme present in the original cytoplasmic fraction, and the presence of surfactants did not change the K m and V m , values. The nucleotidase from this source was a phosphohydrolase of 5′‐mononucleotides acting on the deoxyribonucleotides and ribonucleotides of purines and pyrimidines. 5′‐IMP was the preferred substrate; the optimum pH was 7.5. The study of the influence of the temperature on the initial reaction rates allowed calculation of the δE a , and δH o values. The variation of V m and K m with a change in pH suggests the existence of a sulfhydryl group and an imidazole group in the enzymesubstrate complex.