Comparative Activties of Aspartate Transcarbamylase in Various Tissues of the Rat.

Abstract

The activity of aspartate transcarbamylase [ATC], the enzyme which catalyzes the 1st step unique to pyrimidine biosynthesis, correlates well with mitotic activity in all tissues except brain. Testis, spleen, small intestine, intestinal mucosa, bone marrow, and lung all contain relatively high ATC activities and are all relatively active mitotically, except lung. Moderate ATC levels were found in pancreas, kidney, and liver which all exhibit low mitotic activity. The moderately high ATC activity of brain obviously does not reflect cell division in the central nervous system but may be an indicator of de novo RNA synthesis.