title: Chemical pathology of homocysteine. V. Thioretinamide, thioretinaco, and cystathionine synthase function in degenerative diseases.
abstract: Hyperhomocysteinemia was first associated with degenerative disease by observation of accelerated arteriosclerosis in children with inherited disorders of cystathionine synthase, methionine synthase, and methylene tetrohydrofolate reductase. The metabolic blockade of sulfate synthesis from homocysteine thiolactone in malignant cells is ascribed to a deficiency of a chemopreventive derivative of homocysteine thiolactone that occurs in normal cells. Its chemical structure was elucidated by the organic synthesis of thioretinamide from retinoic acid and homocysteine thiolactone. Oxidation of the sulfur atom of homocysteine is inhibited in scorbutic guinea pigs, demonstrating ascorbate function in sulfate synthesis from homocysteine. Studies of homocysteine metabolism in protein energy malnutrition led to the conclusion that the biosynthesis of thioretinamide from the retinol of transthyretin is catalyzed by dehydroascorbate and superoxide generated from the heme oxygenase group of cystathionine synthase. Newly synthesized thioretinamide is complexed with cobalamin to form thioretinaco, which is activated by ozone and oxygen to function as the active site of oxidative phosphorylation. In accordance with the trophoblastic theory of cancer, pancreatic enzymes are believed to be oncolytic because they hydrolyze the homocysteinylated proteins, nucleic acids and glycosaminoglycans of malignant tissues. The clonal selection of malignant cells that are deficient in the heme oxygenase function of cystathionine synthase produces cells dependent upon glycolysis for ATP synthesis, since they are deficient in synthesis of thioretinamide, thioretinaco and thioretinaco ozonide. The vulnerable plaque of arteriosclerosis originates from complexes of microbes with homocysteinylated lipoproteins, obstructing vasa vasorum narrowed by endothelial dysfunction, causing arterial ischemia, and intimal micro-abscesses. Degenerative diseases may be ameliorated by a proposed therapeutic protocol of thioretinamide with pancreatic enzymes.
authors.affiliation: Veterans Affairs Medical Center, West Roxbury, MA 02132, USA. kilmer.mccully@va.gov
authors.forename: Kilmer S
authors.initials: KS
authors.lastname: McCully
mesh_terms: D003541:Cystathionine beta-Synthase / Q000378:metabolism*; D004194:Disease; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D010084:Oxidation-Reduction; D014212:Tretinoin / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D014805:Vitamin B 12 / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism
chemical_list: C488375:thioretinaco; D006710:Homocysteine; C053232:N-homocysteine thiolactonyl retinamide; D014212:Tretinoin; D003541:Cystathionine beta-Synthase; D014805:Vitamin B 12