The alteration of the functional properties of human haemoglobin by spectrin

Abstract

Kinetic investigation by means of stopped flow techniques showed the rate of deoxygenation of haemoglobin to be slower in the presence of spectrin. At pH 7.15, the kinetic constant was 27.2 sec-1 in presence of spectrin instead of 34.3 sec-1 for haemoglobin alone. Also, equilibrium studies have revealed that the oxygen pressure for half-saturated haemoglobin decreased when spectrin was added to the reaction medium. At pH 7.35, the log (pO2)1/2 was 0.88 for haemoglobin in presence of spectrin instead of 0.93 for haemoglobin alone. From these results, an interaction between spectrin and haemoglobin may be suspected.

Erythrocyte Signal Transduction Pathways, their Oxygenation Dependence and Functional Significance

“…It was shown that spectrin can bind to Hb [50] and slightly increase the Hb-O 2 affinity [51]. The stabilizing effect of Hb on the spectrin tetramer, likewise, implies interaction between these two proteins [52].…”