Metabolic activities of sheep erythrocytes. II. Formate metabolism

Abstract

Whole sheep blood, washed erythrocytes, and haemolysates showed only a slight capacity to oxidize 14C-labelled formate, as measured by labelled carbon dioxide production. Considerable oxidation of formate by washed erythrocytes or haemolysates occurred in the presence of systems generating hydrogen peroxide enzymically or non-enzymically under aerobic conditions. In addition, methylene blue was found to stimulate markedly the aerobic oxidation of formate by erythrocytes and haemolysates, the effect being abolished under anaerobic conditions. The stimulatory effects of methylene blue and sulphydryl compounds were additive. Evidence was obtained that the effect of methylene blue was mediated through an enzyme which directly or indirectly gave rise to hydrogen peroxide, formate oxidation being achieved by a hydrogen peroxide-catalase complex. No evidence was obtained of formate incorporation into red cells.