Abstract
1. The hexokinase activity of homogenates of eggs and embryos of the sea urchin Arbacia punctulata has been measured. Expressed as micrograms glucose consumed at 20°C., per hour per milligram of protein the following values were obtained: unfertilized eggs, 67; fertilized eggs, 72; 24 hour plutei, 94; 48 hour plutei, 226. The concentration of the enzyme in the eggs is small and may be calculated to be about 0.001 per cent of the dry weight of unfertilized eggs. 2. The hexokinase activity of the egg homogenate was virtually all recovered in the supernatant fraction when the homogenate was centrifuged at 20,000 x g for 30 minutes and was found to have the following properties: The concentrations for half maximal hexokinase activity with various substrates were, approximately: Glucose, 0,00003 M; fructose, 0.00075; mannose, 0.00007; 2-desoxyglucose, 0.00025. The relative rates of phosphorylation of various sugars by the supernate fraction when saturated with substrate were, approximately: Glucose, 1.0; mannose, 1.2; fructose, 1.8; 2-desoxyglucose, 2.0; glucosamine, 0.6. Adenosinediphosphate and glucose-6-phosphate inhibited the enzyme. No evidence for more than one hexokinase in the Arbacia extracts was found.
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Selected References
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- CHRISTENSEN W. R., PLIMPTON C. H., BALL E. G. The hexokinase of the rat erythrocyte and the influence of hormonal and other factors on its activity. J Biol Chem. 1949 Sep;180(2):791–802. [PubMed] [Google Scholar]
- CRANE R. K., SOLS A. The association of hexokinase with particulate fractions of brain and other tissue homogenates. J Biol Chem. 1953 Jul;203(1):273–292. [PubMed] [Google Scholar]
- KELTCH A. K., STRITTMATTER C. F., WALTERS C. P., CLOWES G. H. A. Oxidative phosphorylation by a cell-free particulate system from unfertilized arbacia eggs. J Gen Physiol. 1950 May 20;33(5):547–553. doi: 10.1085/jgp.33.5.547. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LONG C. Studies involving enzymic phosphorylation. I. The hexokinase activity of rat tissues. Biochem J. 1952 Jan;50(3):407–415. doi: 10.1042/bj0500407. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- SALTMAN P. Hexokinase in higher plants. J Biol Chem. 1953 Jan;200(1):145–154. [PubMed] [Google Scholar]
- SLEIN M. W., CORI G. T., CORI C. F. A comparative study of hexokinase from yeast and animal tissues. J Biol Chem. 1950 Oct;186(2):763–780. [PubMed] [Google Scholar]
- SOLS A., CRANE R. K. The inhibition of brain hexokinase by adenosinediphosphate and sulfhydryl reagents. J Biol Chem. 1954 Feb;206(2):925–936. [PubMed] [Google Scholar]
- STRITTMATTER P., KELTCH A. K., WALTERS C. P., CLOWES G. H. A. Oxidative phosphorylation by a cell-free, particulate, enzyme system derived from fertilized Arbacia eggs. Biol Bull. 1950 Oct;99(2):333–334. doi: 10.1086/BBLv99n2p321. [DOI] [PubMed] [Google Scholar]
- WEIL-MALHERBE H., BONE A. D. Studies on hexokinase. 1. The hexokinase activity of rat-brain extracts. Biochem J. 1951 Aug;49(3):339–347. doi: 10.1042/bj0490339. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WEIL-MALHERBE H., BONE A. D. Studies on hexokinase. 2. An activator of hexokinase in erythrocytes. Biochem J. 1951 Aug;49(3):348–354. doi: 10.1042/bj0490348. [DOI] [PMC free article] [PubMed] [Google Scholar]