Stability of haemoglobin and of certain endoerythrocytic enzymes in vitro

Abstract

Properties of Hb and of certain endoerythrocytic enzymes were examined in 24- and 42-yr.-old samples of horse blood (A and B respectively) collected aseptically and preserved in the dark at room temp. Blood in these samples was laked and Hb completely deoxygenated. The fact that no bands of hemoehromogen could be detected even on addition of Na2SO4 indicates that no partial denaturation of Hb occurred. The O2 capacity of these samples/rag, dry wt. or /mg. hemin was approx. the same as that of fresh horse blood. The O2 dissociation curve of Hb in sample A was found to be S-shaped and very little different from that of fresh blood, the P50 for blood A and for fresh horse blood being 5.1 and 4.8 mm. Hg respectively. Absolute absorption spectra of oxy-Hb in blood A and of carboxy-Hb in blood B are indistinguishable from those of fresh horse blood. From a 44-yr.-old sample of guinea-pig blood (C) collected and preserved aseptically, crystals of oxy-Hb were obtained of the characteristic tetrahedral type similar in every respect to those prepared from fresh guinea-pig oxy-Hb. The endo-erythrocytic enzymes such as carbonic anhydrase, catalase, glyoxalase, and choline esterase in different samples of blood specimens A and B retained up to 85% of their activities when comparison was made with fresh horse blood. The factors which favored the preservation of Hb and of the enzymes in these blood samples were mainly protection from bacterial infection, absence of O2, protection from light and a high concn. of proteins. Since the conditions of preservation of these blood samples were not perfect, 44 yrs. is probably very far below the possible life span of these proteins in vitro.