Phenotype dependence in the inhibition of red cell acid phosphatase (ACP) by folates.

Red cell acid phosphatase (ACP) is shown to be inhibited by folic acid and various folates. The degree of inhibition is phenotype dependent with a pattern of variation differing from that of the well recognized variation in red cell activity levels. The pattern of variation is ordered ACP1B less than ACP1A less than ACP1C in terms of the relative allelic contributions to the observed inhibition. This pattern correlates with previously observed patterns of risk for two hemolytic disorders and may thus provide a key to their understanding.