Red blood cell rhodanese: its possible role in modulating delta-aminolaevulinate synthetase activity in mammals.

The optimum conditions for measuring rhodanese activity in human erythrocytes were established. The mean control values for males (112 nmol SCN/30 min/mg protein) and females (127 nmol SCN/30 min/mg protein) were determined. Rhodanese activity was measured in different porphyric patients. The activity was diminished in porphyria cutanea tarda (PCT), acute intermittent porphyria (AIP), variegate porphyria (VP) and lead intoxication (Pb), remaining normal in erythropoietic protoporphyria (EPP). delta-Aminolaevulinate synthetase (ALA-S) activity was increased in PCT, AIP, VP and Pb showing no changes in EPP. It is suggested that a similar scheme, to that proposed for the control of ALA-S in Rhodopseudomonas spheroides and soybean callus, is also operating in animals.