Purification and properties of guanylate kinase from bovine retinas and rod outer segments
| Autor: | Scott W. Hall, Hermann Kühn |
|---|---|
| Rok vydání: | 1986 |
| Předmět: |
Guanylate kinase
Guanosine Monophosphate Adenylate kinase Biology Biochemistry Retina Adenosine Triphosphate Animals Photoreceptor Cells Nucleotide chemistry.chemical_classification Molecular mass Kinase Phosphotransferases Rod Cell Outer Segment Peptide Fragments Turnover number Enzyme chemistry Spectrophotometry Cattle Chromatography Thin Layer Nucleoside-Phosphate Kinase Guanylate Kinases |
| Zdroj: | European Journal of Biochemistry. 161:551-556 |
| ISSN: | 1432-1033 0014-2956 |
| DOI: | 10.1111/j.1432-1033.1986.tb10477.x |
| Popis: | The presence of three soluble nucleotide phosphotransferases in bovine rod outer segments was demonstrated: guanylate kinase (EC 2.7.4.8), nucleoside-diphosphate kinase (EC 2.7.4.6) and adenylate kinase (EC 2.7.4.3). The enzyme guanylate kinase, which catalyzes the reaction GMP + ATP in equilibrium GDP + ADP, was purified to homogeneity from isolated bovine rod outer segments as well as from bovine retinas. The enzyme preparations obtained from both sources are identical in their chromatographic properties, molecular mass (20-23 kDa for both native enzyme and dodecylsulfate-denatured polypeptide), Km values (13 microM for GMP and 430 microM for ATP), specific activities, and nucleotide specificities. The enzyme's turnover number was estimated to be 130 s-1. The minimum amount of enzyme found in rod outer segments is about 1 copy per 800 rhodopsin molecules. The role of the enzyme in the cyclic GMP cycle in rod outer segments is discussed. |
| Databáze: | OpenAIRE |
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