Isoelectric focusing studies of human red cell esterase D: evidence for polymorphic occurrence of a new allele EsD7 in Japanese.

The isoelectric focusing study of esterase D in Japanese revealed evidence of a new polymorphic allele (EsD7) which is difficult to find by conventional starch gel electrophoresis only. A comparison with the occurrence of a subdivision of EsD2 in Caucasians (EsD5) suggests a remarkable difference in allele distribution of esterase D among races. Quantitative analysis showed a relatively low value of enzyme activity for this new allele. It is therefore emphasized that in addition to conventional electrophoresis, enzyme assay and further detection by isoelectric focusing are essential in analyzing the esterase D system.