Detection of lactate dehydrogenase B4 in human hemolysate of patients deficient in lactate dehydrogenase B subunit activity using enzyme immunoassay.

We developed a sensitive enzyme immunoassay system specific for human lactate dehydrogenase (LDH)-B4 with antiacetylated LDH-B4 Fab'-horseradish peroxidase conjugate. The enzyme immunoassay system was not interfered with by up to 0.3 mg/tube of hemoglobin. Thus, we measured LDH-B4 concentrations in the hemolysate of seven heterozygous individuals deficient in LDH-B subunit activity and eight normal individuals. We could not find a significant difference between the LDH-B4 concentrations in heterozygous and those in normal individuals. These results demonstrate that heterozygous individuals deficient in LDH-B subunit activity produce enzymatically inactive B subunits.