3:4-Dihydroxyphenzylalanine and biosynthesis of cholesterol in vivo and in vitro experimental studies.
In vitro incubation of 24 amino acids with frog liver homogenate shows 4 grades of cholesterogenic values. 1. Alanine, Phenylalanine, Tyrosine and DOPA give positive results. Other amino acids were able to sustain the original amounts of cholesterol to different proportions e.g. 2. Aspartic acid, Proline and Valine (50%). 3. Sodium Acetate, Arginine, Cysteine, Leucine, Norleucine, Methionine and Serine (more than 50%). 4. Aminobutyric, Glutamic, Glycine, Histidine, Hydroxyproline, Isoleucine, Lysine, Ornithine, Threonine and Tryptophan (less than 50% to negligible). DOPA gives the maximum yield of 73.1% It also shows high cholesterogenic values in different organs both in vitro and in vivo. It is thus a major precursor of cholesterol in animal tissues. Scheme of biosynthesis of cholesterol from DOPA ARE GIVEN ON THE BASIS OF KNOWN FACTS. A postulated scheme of direct synthesis of sterid molecule from DOPA is also provided. DOPA also showns sympathomimetic effects upon subcutaneous administration and blood cholesterol is reduced to more than 50%. Although there are numerous publications detailing the various aspects of biosynthesis of cholesterol and hyper and hypo-cholesterolemia yet the exact realtionship between the amino acids and cholesterol synthesis is not properly understood. Recent publications of Shrivastava (1975 a,b,c) have aspecially drawn attention to the high cholesterogenic effects of 3:4-dihydroxyphenylalanine. This work presents evidence that DOPA is infact a major and potential source of cholesterol not only in liver but in other animal tissues as well.
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002784:Cholesterol / Q000096:biosynthesis*; D004295:Dihydroxyphenylalanine / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D011898:Ranidae
D000596:Amino Acids; D004295:Dihydroxyphenylalanine; D002784:Cholesterol