α-Lactalbumin and the Lactose Synthetase Reaction

Autor: I. Kiyosawa, B. Colvin, R. Mawal, D.K. Fitzgerald, K.E. Ebner, Urs Brodbeck
Rok vydání: 1970
Předmět:
Zdroj: Journal of Biological Chemistry. 245:2103-2108
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)63212-0
Popis: An improved procedure for the isolation of the A protein of lactose synthetase is presented. The Km for UDP-galactose is not influenced by the concentration of glucose or α-lactalbumin but these compounds alter the maximum velocity of the reaction. There is a reciprocal relationship between the concentration of glucose and α-lactalbumin in the lactose synthetase assay and α-lactalbumin lowers the apparent Km of glucose. It is suggested that the physiological function of α-lactalbumin is to lower the Km of glucose so that it may be used maximally for the synthesis of lactose. Lactose may be synthesized at maximum rates by the A protein in the absence of α-lactalbumin but in the presence of high concentrations of glucose. Different preparations of the A protein have variable activities.
Databáze: OpenAIRE