[Citrate synthesis by reductive carboxylation of alpha-ketoglutarate in rumen tissue of cattle and sheep].

In the cattle rumen mucosa the citrate synthesis from alpha-ketoglutarate and CO2 is activated by ATP and biotin; in the muscular tissue ATP or biotin separately does not affect this process. Mn2+, Zn2+, Mg2+, Co2+, Cd2+ and cystein favour citrate synthesis; citrate is not formed in the presence of Fe2+. For homogenates prepared on the borate buffer, the rate of an increase in the citrate content is higher than for homogenates on the phosphate or tris-HCl-buffer. In the muscular tissue of the lamb rumen this index is greater than in the sheep, and in the mucosa cattle, sheep and lamb the intensity of the reaction is the same.