Hepatic Glucose Phosphotransferases Variations Among Species

Glucokinase activity (ATP :D-glucose-6-phosphotransferase, E.C. 2.7.1.2) was assayed in various species, including man (Homo sapiens). Low or absent activities were found in the toadfish (Opsanus tau) cat (Felis domesticus), guinea pig (Cavia porcellus), calf (Bos taurus), and man, and higher activities in the bullfrog (Rana catesbeiana), dog (Canis familiaris), rabbit (Oryctolagus cuniculus), mouse (Mus musculus), rat (Rattus norwegicus), and sand rat (Psammomys obesus). Fasted mice and dogs failed to show a decrease in activity. Sand rats with spontaneous diabetes or rendered diabetic by diet also failed to show a reduction in activity. The role of the enzyme in the regulation of blood glucose concentration remains speculative.