The synthesis of glycine and serine by the rat

Arnstein, H. R. V.; Neuberger, A.

doi:10.1042/bj0550271

Cited by 60 publications

(33 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The following series of reactions has been proposed [21,22] The observations, in our control subjects, that glycine infusion increased rather than decreased the metabolism of glycine to CO 2 and appeared also to increase the formation of the /S carbon of serine from glycine, suggest that large amounts of glycine may stimulate reaction 1. The data are consistent with the experiences of ARNSTEIN and NEUBERGER [2] who found greater rates of conversion of glycine to serine in rats fed diets with a higher than usual content of glycine. The interpretation that the conversion of glycine to serine may operate physiologically only in the presence of large quantities of glycine is not consistent with observations in hyperglycinemia.…”

Section: Discussionsupporting

confidence: 82%

“…The specific activities of the serine isolated from plasma after the injection of glycine- [1][2][3][4][5][6][7][8][9][10][11][12][13][14] C are shown in table II. In the control subjects, in the absence of a glycine-infused state, the specific activities of serine decreased sharply from maxima at the earliest times studied.…”

Section: Conversion Of Glycine To Serinementioning

confidence: 99%

See 1 more Smart Citation

Metabolism of Glycine in the Nonketotic Form of Hyperglycinemia

et al. 1968

View full text Add to dashboard Cite

Hyperglycinemia is a disorder of amino acid metabolism characterized by the presence of increased concentrations of glycine in the blood, urine, and cerebrospinal fluid. It is now recognized that there are two forms of hyperglycinemia each representing distinct diseases. These studies were designed to assess the metabolism of glycine in the nonketotic form of hyperglycinemia. Isotope content was assessed in respiratory CO 2 and in glycine, serine and the /? carbon of serine of plasma after the separate intravenous injections of glycine-1-14 C and glycine-2-14 C. The specific activities of 14 CO 2 isolated from expired air after the injection of glycine-1-14 G ( fig. 2) declined in control subjects from peak values at 10 to 15 minutes in nearly linear fashion over a 2-hour period. In contrast, curves obtained in the patients were rather flat, rising slowly after injection to highest values at about 60 minutes. At 15 minutes, values for the control individuals exceeded those of the patients by a factor of 5-to 10-fold. These data indicate a defect in the formation of 14 CO 2 from the first carbon of glycine. When the control subjects were infused with nonisotopic glycine to produce pools comparable to those found in the patient, the specific activities of the serine isolated from plasma after the injection of glycine-1-14 C (table II) were virtually the same in both groups. The rate of conversion of glycine-2-14 C to serine ( fig. 3) in the patients was, however, considerably slower than it was in the control subjects for at least the first 30 minutes, and the curves were flat throughout. Degradation of the serine isolated from plasma and precipitation of the /S carbon as formaldemethone indicated that the incorporation of the a carbon of glycine into the /? carbon of serine was much higher in the controls than in the patients (fig. 4). The curves for the patients approximated the abscissa indicating virtually no conversion.These data indicate that in nonketotic hyperglycinemia there is a defect in the oxidation of carbon 1 of glycine to CO 2 and in the conversion of carbon 2 of glycine to carbon 3 of serine. This is consistent with a defect in an enzyme catalyzing the transformation of glycine to CO 2 , NH 3 and hydroxymethyltetrahydrofolate. SpeculationThe data obtained indicate that patients with nonketotic hyperglycinemia are unable in vivo to convert the first carbon of glycine directly to CO 2 and the second carbon of glycine to the third carbon of serine. This is consistent with a genetic defect in an enzyme which catalyzes decarboxylation and formation of hydroxymethyl tetrahydrofolate from glycine. It should be possible to document such a defect at a cellular and subcellular level.

show abstract

Section: Discussionsupporting

confidence: 82%

Section: Conversion Of Glycine To Serinementioning

confidence: 99%

Metabolism of Glycine in the Nonketotic Form of Hyperglycinemia

et al. 1968

View full text Add to dashboard Cite

show abstract

“…Turnover rates of 1.05 m-moles/kg./hr. (Arnstein & Neuberger, 1953) and 1 e13 m-moles/kg./ hr. Arnstein & Stankovic (1956) have been reported for the rat, and a value of 1-66 m-moles/kg./ hr.…”

Section: Discussionmentioning

confidence: 93%

The first glycine metabolic pool in man

Watts

Crawhall

1959

Biochemical Journal

View full text Add to dashboard Cite

“…Furthermore (15) reported glycine turnover in the rat of 1 mmole per kg per hour in experiments in which the specific activities of the glycine of tissue proteins were measured after feeding of isotopic glycine. The similarity of the orders of magnitude obtained in three quite different experiments on two mammalian species is striking.…”

Section: Resultsmentioning

confidence: 99%