The genetic control of arylesterase activity in the serum of Gotland Sheep

Esterase activity was determined in 955 serum samples of Gotland sheep. The activities showed a wide range and could be distinguished in six types. Family data were in agreement with the theory of three multiple alleles controlling the esterase activities (Lee, 1966). The following gene frequencies were estimated: Es ^a= 0.15, Es ^b= 0.75 and Es ^c= 0.10. The Es ^a allele controlled an enzym with high hydrolysis rate of α-naphthyl acetate, medium high of β-naphthyl acetate and low of indophenyl acetate. The enzym controlled by the Es ^b allele had medium high hydrolysis rate of α- and β-naphthyl acetate and relatively high of indophenyl acetate. The enzym of the Es ^c allele had low activities for all three substrates. The hydrolysis rate was increased by the addition of calcium. In starch-gel electrophoresis the esterase types could be divided in four groups due to the staining intensity of the arylesterase zone but no difference in migration rates was observed.