Aminotransferases alkylation

D-bifunctional protein deficiency [5], 2-methyl acyl-CoA racemase (AMACR) deficiency [3] and sterol carrier protein (SCP-x) deficiency [6], the disorders of etherphospholipid biosynthesis (dihydroxyacetone phosphate acyltransferase and alkyl- dihydroxyacetone phosphate synthase deficiency) [2], the disorders of phytanic acid alpha-oxidation (Refsum disease) [15], and the disorders of glyoxylate detoxification with hyperoxaluria type 1 as caused by alanine glyoxylate aminotransferase deficiency as a sole representative. 

Most of the synthetic androgens and anabolic agents are 17-alkyl-substituted steroids. Administration of drugs with this structure is often associated with evidence of hepatic dysfunction, eg, increase in sulfobromophthalein retention and aspartate aminotransferase (AST) levels. Alkaline phosphatase values are also elevated. These changes usually occur early in the course of treatment, and the degree is proportionate to the dose. Bilirubin levels occasionally increase until clinical jaundice is apparent. The cholestatic jaundice is reversible upon cessation of therapy, and permanent changes do not occur. In older males, prostatic hyperplasia may develop, causing urinary retention. 

Topaquinone (TPQ), the oxidized form of 2,4,5-trihydroxyphenylalanine (TOPA), is the cofactor of copper-containing amine oxidases. The following model compounds have been prepared in order to understand the catalytic function of TPQ the jV-pivaloyl derivative of 6-hydroxydopamine in aqueous acetonitrile [38] topaquinone hydantoin and a series of 2-hydroxy-5-alkyl-l,4-benzoquinones in anhydrous acetonitrile (o- as well as />-quinones) [39] 2-hydroxy-5-methy 1-1,4-benzoquinone in aqueous system [40] and 2,5-dihydroxy-1,4-benzoquinone [41]. Reaction of model compounds with 3-pyrrolines revealed why copper-quinopro-tein amine oxidases cannot oxidize a secondary N [42], The studies clearly showed that certain model compounds do not require the presence of Cu for benzylamine oxidation whereas TPQ does [38,40] the aminotransferase mechanism proceeds via the -quinone form [39] the 470 nm band can be ascribed to a 71-71 transition of TPQ in />-quinonic form with the C-4 hydroxyl ionized but hydrogen bonded to some residue [40] hydrazines attack at the C-5 carbonyl, forming an adduct in the azo form [41], Electrochemical characterization has been carried out for free TPQ [43],... 

Water retention due to sodium chloride (salt) is a common manifestation that leads to weight gain. Edema is also found in patients with cardiac heart failure, renal insufficiency, liver cirrhosis, and hypo-proteinemia. When large doses are used to treat neoplastic diseases, compounds with 17-alkyl substitutions can cause cholestatic hepatitis at high doses, jaundice is the most common clinical feature with accumulation of bile in the bile capillaries. Jaundice usually develops after 2-5 months of therapy. It can be detected by increases in plasma aspartate aminotransferase and alkaline phosphatase. 

Aminotransferases are potentially applicable to the production of a wide range of amino acids, because enzymes are available for d- and L-amino acids. In addition, a wide range of aminotransferases with side-chain specifidty are known, including enzymes for the production of amino acids with aromatic side chains, acidic side chains, branched alkyl side chains, etc. 

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