Propionyl-CoA synthetase in mammary gland and liver of cows.

Propionyl-CoA synthetase of liver and mammary gland from calf and midlactation cow was investigated. No activity of this enzyme was detected in calf mammary gland, but it was detected in calf liver. Propionyl-CoA synthetase was found in both, liver and mammary gland of the cow, although mammary gland activity was about 25% of that found in liver. The effects of pH and temperature on enzyme activity and stability were also investigated in crude extracts of liver and mammary gland tissues. The results suggest a different behaviour of the enzyme from both origins. Kinetic studies of the enzyme were also carried out, showing differences, depending on the organ, in the apparent substrate KM values.