Effects of sulphydryl compounds on abnormal red cell pyruvate kinase.

The effect of some sulphydryl compounds on two new variants of red cell pyruvate kinase (ATP: pyruvate phosphotransferase, PK) is reported. In vitro a striking correction has been obtained of both the qualitative and, in one case, the quantitative defect of red cell PK. In vivo, a correction of the qualitative and quantitative abnormalities has been produced in both patients, with clinical improvement of one of them. These findings, together with the unexpected results in respect to the functional properties of PK found in the affected members of the two families studied, suggest that the PK abnormality is not the cause of the haemolytic anaemia, but an epiphenomenon of a primary unknown defect that apparently involves the red cell thiol groups.