Nongenetic determinants of human serum esterases.

A panel of 1151 unselected individuals was screened by starch gel electrophoresis for serum esterase variants. Two types of variants were observed which were shown by family studies not to be genetically determined. No consistent disease process was correlated with the occurrence of these variants. Suggestive evidence has been obtained to support the hypothesis that these variant proteins were produced by the action of exogenous neuraminidase on the individuals' normal C, esterases. A third type of variant enzyme was observed in 1 patient. This enzyme was shown to be a substantially larger molecule than the C, esterase and it is suggested that this protein may be a polymer of the C, esterase.