Choline phosphotransferase and phosphatidyl ethanolamine methyltransferase activities

Abstract 1. 1. The two enzymes, choline phosphotransferase and phosphatidyl ethanolamine methyl-transferase involved in phosphatidyl choline biosynthesis has been assayed in liver homogenates, nuclear, mitochondria and microsome of female rats. 2. 2. These two enzymes are microsomal and a tissue distribution study of liver, kidney, spleen, lung, heart, and brain showed liver having the greatest activity. 3. 3. A species study showed the greatest activity of phosphatidyl ethanolainine methyltransferase in liver microsomes in mouse, chicken, rat, dog, pigeon, human, beef, rabbit, turtle, guinea pig respectively. Choline phosphotransferase activity in liver microsomes decreased in chicken, mouse, human, rat, rabbit, turtle, pigeon, guinea pig, beef and dog, respectively. 4. 4. Female rats fed a purified 25 % casein diet decreased significantly the activity of choline phospho-transferase when compared to Purina lab chow. Intraperitoneal injection daily of 30 mg choline chloride decreases significantly the activity of phosphatidyl ethanolamine methyltransferase.