Cysteine sulfinate aminotransferase

Some pyridoxal phosphate-dependent enzymes are normally fuUy saturated with cofactor and show the same activity on assay in vitro whether additional pyridoxal phosphate is present in the incubation medium or not. Examples of this class of enzymes include liver cysteine sulfinate decarboxylase (which is involved in the synthesis of taurine from cysteine Section 14.5.1) and the brain and liver glutamate and aspartate aminotransferases. 

Lin C-T, Li J-Z, Wu J-Y (1983) Immunocytochemical localization of L-glutamate decarboxylase, gamma-aminobutyric acid transaminase, cysteine sulfinic acid decarboxylase, aspartate aminotransferase and somatostatin in rat retina. Brain Res 270 273-283. 

Recasens M, Delaunoy JP (1981) Immunological properties and immunocytochemical localization of cysteine sulfinate or aspartate aminotransferase-isoenzymes in rat CNS. Brain Res 205 351-361. 

Naphthylamine D-Amino acid oxidase Rhodotorula gracilis), L-aspartate aminotransferase Esch ichia coli) (rflc)-2-Naphtylamine + cysteine sulfinic acid DE [50]... 

For the preparation of 2-naphthyl alanine, a one-pot, two-step enzyme cascade was invented with d-AAO from Rhodotorula gracilis and an L-aminotransferase from E. coli [50]. Detail information about the deracemization steps was provided in Section 29.3.1 and shown in Scheme 29.3. Starting with the racemic 2-naphthyl alanine, the AAO generated the corresponding a-keto acid, which served as rfie substrate in the reductive amination step to enantiopure 2-naphthyl alanine. An irreversible amino donor, cysteine sulfinic acid, was used. 

Fig. 20.3 Pathway of methionine metabolism. The numbers represent the following enzymes or sequences (1) methionine adenosyltransferase (2) S-adenosylmethionine-dependent transmethylation reactions (3) glycine methyltransferase (4) S-adenosylhomocysteine hydrolase (5) betaine-homocysteine methyltransferase (6) 5-methyltetrahydrofolate homocysteine methyltransferase (7) serine hydroxymethyltransferase (8) 5,10-methylenetetrahydrofolate reductase (9) S-adenosylmethionine decarboxylase (10) spermidine and spermine synthases (11) methylthio-adenosine phosphorylase (12) conversion of methylthioribose to methionine (13) cystathionine P-synthase (14) cystathionine y-lyase (15) cysteine dioxygenase (16) cysteine suplhinate decarboxylase (17) hypotaurine NAD oxidoreductase (18) cysteine sulphintite a-oxoglutarate aminotransferase (19) sulfine oxidase. MeCbl = methylcobalamin PLP = pyridoxal phosphate...

---