| Literature DB >> 239941 |
V Macchia1, S Varrone1, H Weissbach2, D L Miller2, I Pastan3.
Abstract
Guanylate cyclase has been purified from extracts of Escherichia coli. After a 1000-fold purification, the enzyme contains only minor contaminants as judged by disc gel electrophoresis. The Km for GTP is approximately 7 times 10(-5) M and the optimal pH is 8.0. More activity is observed with Mn2+ than with Mg2+, and maximal activity is observed at 0.14 mM Mn2+ and 1.4 mM Mg2+. Based on its behavior on Sephadex G-100, the molecular weight of E. coli guanylate cyclase is about 30,000. Disc gel electrophoretic analysis indicates that the enzyme consists of a single polypeptide chain. Guanylate cyclase does not form 3':5'-AMP from ATP, and therefore, is distinct from adenylate cyclase.Entities:
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Year: 1975 PMID： 239941
Source DB: PubMed Journal: J Biol Chem ISSN： 0021-9258 Impact factor: 5.157