ISSN:
1750-3841
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
SUMMARY: A 5′-nucleotidase, widely distributed in teleost fish muscles, was purified about 20-fold from Pacific cod (Gadus macrocephalus) by chromatography of a dialyzed aqueous extract of the muscle on DEAE-cellulose. The enzyme was unstable and lost 85% of its activity in 1 hr at 37°C 53% in 10 min at 42°C and 40% in 1 hr at 30°C. It was stable for 6 days at 0°C, could be dialyzed for up to 3 days at 0°C against 1 mM tris buffer pH 7.5 and quickly frozen and thawed without loss of activity. However, it was inactivated rapidly when held at −30°C. Brief exposure to pH 4.0 or 5.0 effected marked destruction. Attempts at further purification by means of chromatography on hydroxylapatite, adsorption using alumina Cγ and starch gel electrophoresis failed due to instability.The enzyme was strongly inhibited by EDTA, pyrophosphate, KF and ZnCl2 (1-10 mM); less markedly inhibited by GSH, 2-mercaptoethanol, carbonate and CaCl2 (10 to 100 mM). It was strongly activated by Mn++ and weakly activated by Mg++. The optimum pH was 7.6, and the Km was 5 × 10−4M with UMP and 8 −4M with IMP. It hydrolyzed, in order of effectiveness, LJMP, IMP, CMP, d-AMP, GMP, d-IMP, d-GMP, d-UMP and AMP, but not p-nitro phenylphosphate, sugar phosphates or a number of other compounds including 2′,3′-nucleotides.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2621.1969.tb12110.x
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