31. The systematic name of this enzyme class is "'glutathione : cystine oxidoreductase " '. 32. Will cystine , proline, leucine, water and egg albumin change color with the biuret reagent test? 33. In this environment, cysteines are, in general, oxidized to cystine and are no longer functional as a nucleophiles. 34. L-cysteine also serves as a precursor to cystine which in turn serves as a substrate for the mGluR 5. 35. Together, the light and heavy chains form two identical 73-kDa monomers connected by a cystine bridge at Cys153. 36. Proximal glial cells use a cystine / glutamate antiporter ( xCT ) to transport cystine into the cell and glutamate out. 37. Proximal glial cells use a cystine / glutamate antiporter ( xCT ) to transport cystine into the cell and glutamate out. 38. "' Cystinosis "'is a lysosomal storage disease characterized by the abnormal accumulation of the amino acid cystine . 39. It is rich in phenylalanine and threonine, but limiting in the sulphur amino acids, cystine and methionine, and tryptophan. 40. The structure of atracotoxin comprises a core beta region with a cystine knot motif, a feature seen in other neurotoxic polypeptides.
