GENETICS OF ESTERASES IN MAN

Cholinesterase, arylesterase, and lipoprotein parameters in twins

A high heritability estimate was obtained for serum arylesterase activity level in a series of 40 male twin pairs (23 MZ, 17 DZ) aged 33-39 years. The heritability estimated for cholinesterase activity was strikingly lower. In unrelated individuals a positive correlation between arylesterase, cholinesterase, and various lipoprotein parameters appeared to support the suggestion that these enzymes interact with various lipoproteins at the molecular level. The nature of these associations is not known. It is, however, tempting to speculate that some of the hereditary influence on lipoprotein levels in man may be mediated through the genetic control of one or both of these enzymes.

On the geographical distribution of pseudocholinesterase variants

The incidence of pseudocholinesterase (PCHE equals E.C. 3.1.1.8) variants in samples of 8 different population (total of 2218 individuals) is reported. Together with previously mentioned data from the literature, a general survey on the geographical distribution of PCHE isoenzymes is given. Possible reasons for present-day heterogeneity of their distribution are also discussed. Concerning the incidence of the C5 variant, it is pointed out that the validity of applying population genetic models depends upon the accuracy of the genetic basis.

Parotid saliva enzymes in Down's syndrome

The parotid saliva in persons with Down's syndrome was analyzed for three enzymes: acid phosphatase, nonspecific esterase, and amylase. The results have shown a statistically significant elevation of esterase activity in persons with Down's syndrome whereas no statistical differences were observed with the other enzymes. The current investigation has provided further insight into salivary gland metabolism and may have yielded some information pertaining to the genetic control of the processes regulating the electrolyte concentration of human saliva.

Genetic studies of isozymes in Neurospora. II. Esterases

Acrylamide gel electrophoretic analysis of mycelial extracts revealed that a slow moving esterase is specific to Neurospora crassa strains and a fast moving esterase to N. sitophila strains. These two isozymes of esterases appear to be under the control of two unlinked, codominant duplicate genes.