| Autor: |
Fantl, P., Rome, M. Noël, Nelson, J. F. |
| Zdroj: |
Australian Journal of Experimental Biology & Medical Science; Jun1942, Vol. 20 Issue 2, p121-124, 4p |
| Abstrakt: |
The enzyme complex in liver which forms glucose from glycogen is present mainly in the two-form in fasting as well as fed rabbits. This enzyme system has a maximum activity at pH 6.6 ± 0.1 with a greatly diminished activity on both sides of the apex, suggesting that the pH of the liver may be a factor in blood sugar regulation. The same pH optimum is found for liver extracts in which the phosphatase activity is partially inhibited by a high concentration of inorganic phosphate. The breakdown of hexose-6-PO4 is independent of pH between pH 5-6 and 7-6, whereas the breakdown of added glucose-l-PO4 increases with decreasing acidity owing to the activity of phosphoglueomutase in liver extracts. Calculations of the reaction constant for the breakdown of glycogen frequently give constant figures, indicating that the glucose formed had no inhibitory influence on the breakdown. Added glucose in high concentrations, such as would not be found in the normal intact cell, had some inhibitory influence on the glycogen breakdown. This suggests that under normal conditions glucose cannot be a significant factor in the regulation of blood sugar. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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