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pubmed:abstractText |
A disturbance of serine-glycine metabolism in a group of patients who became psychotic after oral intake of serine may be due to any serine-related enzyme abnormality. In order to elucidate this problem, we studied several enzymes in fibroblasts obtained from these patients. First, the enzyme serine hydroxymethyltransferase was investigated. The apparent Km values for serine, L-tetrahydrofolate (H4folate), and pyridoxal 5'-phosphate, as well as the maximal velocities of the forward and backward reactions measured in fibroblasts obtained from patients, were not different from those in the cells from controls. We also measured the activities of another three enzymes of the folic acid cycle, viz., 5,10-methylene-H4folate dehydrogenase, 10-formyl-H4folate synthetase, and 5,10-methenyl-H4folate cyclohydrolase, as well as the enzyme cystathionine beta-synthase. Again, no differences were found among these enzymes in fibroblasts from patients and controls. It can be concluded that the psychotic symptoms occurring after the administration of serine are not the result of any malfunctioning of the enzymes investigated.
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