1995 Volume 41 Issue 2 Pages 197-205
Hepatic cystathionine β-synthase activity is decreased by the addition of cysteine to the diet. This effect of cysteine was slightly greater in diets containing 0.25% methionine than in those containing 1 % methionine, and was reduced during aging. Similar changes were ob-served in the level of the mRNA of this enzyme, although the changes in the trancscript levels were slightly greater than the changes in enzyme activity. Thus, we conclude that the addition of cysteine to a methionine-containing diet causes a decrease in cystathionine Q-synthase activity mainly by diminishing its mRNA level.
