A girl with hyperglycinemia of nonketotic type was presented. The liver biopsied from the patient was studied for glycine metabolism. It was found that the yield of 14C02 from glycine-l-14C and the rate of 11C incorporation into serine from glycine-1 -14 IC as well as glycine-2 14C were extremely low in the patient's liver than in control livers, while the patient's liver showed normal activities of serine-hydroxymethylase and serine-dehydratase.hese findings indicate that the primary lesion of hyperglycinemia of nonketotic type is a defect in the glycine cleavage reaction which gives rise to the formation of CO2, methylene-tetrahydrofolate and ammonia from glycine.

Clinical and biochemical findings of two siblings with formiminotransferase deficiency syndrome in a family were described and a hereditary background of this disorder was suggested.

No abstract

A probably new entity of metabolic error of folic acid was described of an infant whose clinical and biochemical characteristics were: 1) mental retarda tion and a marked dilatation of cerebral ventricles, 2) abnormally high serum L. casei folate activity, 3) abnormally high levels of folate precursor in erythrocytes, and 4) a marked rise in reticulocyte count by an exogenous folate supplementation.The results of investigation on tetrahydrofolate -dependent enzymes of liver specimens revealed a decreased activity of N5 methyltetrahydrofolate transferase of our own patient.It seems therefore likely that an impaired utilization of N5 methyltetrahy drofolate and its precursor in tissues due to a decreased activity of N5 methyl tetrahydrofolate transferase led to an abnormal accumulation of N5 methyl tetrahydrofolate and its precursor in serum and erythrocytes, and that trapping of folate compounds at an N5 methyltetrahydrofolate level caused a functional deficiency of folates with sequence of development of a megaloblastic change in the bone marrow and of an impaired purine biosynthesis of the brain with a marked dilatation of cerebral ventricles.

Urinary excretion of formiminoglutamic acid (FIGLU) following an oral, intraperitoneal, intramuscular, or intravenous load with L-histidine-monohydro chloride was markedly reduced in rats when fed on a riboflavin deficient diet for 11-30 days.The assay of tetrahydrofolate-dependent enzyme activity of the liver revealed that there were a marked deeraase in the activity of N5,10 methylenetetrahydro folate ieductase and a considerable decrease in that of N5 methyltetrahydro folate transferase of the liver from the riboflavin deficient rats. Results of bioassay using L. casei, St. faecalis and Pediococeus cerevisiae of folate compounds of the liver revealed a tendency toward relative increase in folato deriva tives other than N5 methyltetrahydrofolate in the liver of riboflavin deficient rats.From these results it was assumed that a decreased activity in both the N5,10 methylenetetrahydrofolate reductase and N5 methyltetrahydrofolate trans ferase was induced by riboflavin deficiency, and then that the decrease in the activity of the both enzymes caused an accumulation of tetrahydrofolate com pounds other than N5 methyltetrahydrofolate, thus affording a relatively large amount of free tetrahydrofolate available for the formiminotransferase reac tion, with a consequence of rapid conversion of FIGLU into glutamic acid.Free methionine levels of the liver was not found to be increased but slightly decreased in riboflavin deficient rats as compared with those of control rats.The present investigation demonstrated that urinary excretion of FIGLU after histidine loading by oral, intramuscular, intraperitoneal and intravenous routes was markedly reduced in rats with riboflavin deficiency than those in control rats. For explanation of the mechanism by which a marked reduction in urinary FIGLU was induced by riboflavin deficiency in rats, we examined the activities of tetrahydrofolate-depen dent enzymes of the liver and also carried out analysis of folate compounds of the liver using L. casei, St. faecalis and P. cerevisiae as test organisms.The results obtained led us to the conclusion that: 1) riboflavin deficiency causes a marked decrease in N5,10 methylenetetrahydrofolate reductase activity and a considerable decrease in N5 methyltetrahydrofolate transferase activity of the