Abstract HOMOCYSTINURIA cases are now considered second in number to those of phenylketonuria (PKU). Still the number of cases available to any one investigator for study and treatment is limited. Two points must be made by way of introduction to a consideration of the treatment of homocystinuria: (1) methionine is not elevated in the blood of all homocystinurics and (2) homocystinuria is in all likelihood differentiated from the clinical condition described as hypermethioninemia in which homocystine is not excreted. It is quite clear that the enzymic block in homocystinuria is in the enzyme cystathionine synthase, also known as serine dehydrase. This enzyme in the rat is apparently able to act in the conversion of homocystine to cystine in the presence of serine, and can also function in the conversion of serine to pyruvate.1 Suda and co-workers2 have shown that cystine inhibits this enzyme in rat liver and this may References 1. Selim, A.S.S.M., and Greenberg, D.M.: Further Studies on Cystathionine Synthetase-Serine Deaminase of Rat Liver , Biochim Biophys Acta 42:211, 1960.Crossref 2. Kato, A., et al: Control Mechanism in the Rat Liver Enzyme System Converting L-Methionine to L-Cystine , J Biochem 55:401, 1964. 3. Peraino, C.; Lamar, C., Jr.; and Pitot, H.C.: Studies on the Induction and Repression of Enzymes in Rat Liver , J Biol Chem 241:2944, 1966. 4. Brenton, D.P., et al: Homocystinuria: Clinical and Dietary Studies , Quart J Med 35:325, 1966. 5. Klavins, J.V., and Johansen, P.V.: Pathology of Amino Acid Excess , Arch Path 79:600, 1965.
American Journal of Diseases of Children – American Medical Association
Published: Jan 1, 1967