A POSSIBLE ROLE OF ADENYLATE METABOLISM IN HUMAN ERYTHROCYTES - SIMPLE MATHEMATICAL-MODEL

A simplified mathematical model of cell metabolism describing ion pump , glycolysis and adenylate metabolism was developed and investigated i n order to clarify the functional role of the adenylate metabolism sys tem in human erythrocytes. The adenylate metabolism system was shown t o be able to function as a specific regulatory system stabilizing intr acellular ion concentration and, hence, erythrocyte volume under chang es in the permeability of cell membrane. This stabilization is provide d via an increase in adenylate pool in association with ATPases rate e levation. Proper regulation of adenylate pool size might be achieved e ven in the case when AMP synthesis rate remains constant and only AMP degradation rate varies. The best stabilization of intracellular ion c oncentration in the model is attained when the rate of AMP destruction is directly proportional to ATP concentration and is inversely propor tional to AMP concentration. An optimal rate of adenylate metabolism i n erythrocytes ranges from several tenths of a percent to several perc ent of the glycolytic flux. An increase in this rate results in deteri oration of cell metabolism stability. Decrease in the rate of adenylat e metabolism makes the functioning of this metabolic system inefficien t, because the time necessary to achieve stabilization of intracellula r ion concentration becomes comparable with erythrocyte life span. (C) 1996 Academic Press Limited.