A New Atp-Forming Reaction: The Reductive Deamination of Glycine

Stadtman, Thressa C.; Elliott, Patricia

doi:10.1021/ja01590a076

Cited by 30 publications

(9 citation statements)

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“…29 Glycine oxidase also catalyzes deamination of glycine and other amino acids. 29,30 Mechanistic study of this enzymatic reaction by Molla et al showed its reversible nature. 30 Glycine is also utilized by many anaerobic bacteria, 31,32 conveying it in a reductive deamination, yielding acetic acid and ammonia.…”

Section: Introductionmentioning

confidence: 99%

On the Mechanism and Rate of Spontaneous Decomposition of Amino Acids

Alexandrova

Jorgensen

2011

J. Phys. Chem. B

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Spontaneous decarboxylation of amino acids is among the slowest known reactions; it is much less facile than the cleavage of amide bonds in polypeptides. Establishment of the kinetics and mechanisms for this fundamental reaction is important for gauging the proficiency of enzymes. In the present study, multiple mechanisms for glycine decomposition in water are explored using QM/MM Monte Carlo simulations and free energy perturbation theory. Simple CO2 detachment emerges as the preferred pathway for decarboxylation; it is followed by water-assisted proton transfer to yield the products, CO2 and methylamine. The computed free energy of activation of 45 kcal/mol, and the resulting rate-constant of 1 × 10−21 s−1, can be compared with an extrapolated experimental rate constant of ~2 × 10−17 s−1 at 25 °C. The half-life for the reaction is more than 1 billion years. Furthermore, examination of deamination finds simple NH3-detachment yielding α-lactone to be the favored route, though it is less facile than decarboxylation by kcal/mol. Ab initio and DFT calculations with the CPCM hydration model were also carried out for the reactions; the computed free energies of activation for glycine decarboxylation agree with the QM/MM result, while deamination is predicted to be more favorable. QM/MM calculations were also performed for decarboxylation of alanine; the computed barrier is 2 kcal/mol higher than for glycine in qualitative accord with experiment.

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Section: Introductionmentioning

confidence: 99%

On the Mechanism and Rate of Spontaneous Decomposition of Amino Acids

Alexandrova

Jorgensen

2011

J. Phys. Chem. B

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“…Furthermore, glycine-dependent ATP production could be observed during this reaction. Cell-free extracts of C. sticklandii showed a somewhat lower activity of the enzyme although the value was about 10-fold higher than those reported by Stadtman & Elliott (1956). This might be due to the more gentle storage conditions established by Barnard & Akhtar (1979) and also used by us.…”

Section: -4mentioning

confidence: 48%

“…The reaction catalysed by glycine reductase was discovered by Stadtman & Elliott (1956) while investigating the degradation of glycine and other amino acids in a Stickland reaction by C . sticklandii.…”

Section: Selenium-dependent Glycine Fermentation 1463 D I S C U S S Imentioning

confidence: 99%

Selenium-dependent Growth and Glycine Fermentation by Clostridium purinolyticum

Dürre

Andreesen

1982

Microbiology

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Clostridium purinolyticum fermented glycine as a sole carbon and energy source according to the equation:The organism required adenine as a supplement and selenium compounds as micronutrients for growth. The molar growth yield on glycine was 6.5 g dry wt. Radiochemical and enzymic investigations revealed a new fermentation pathway for glycine in which 1 mol glycine was completely oxidized to CO, and the generated reducing equivalents were used to reduce a further 3 mol glycine to acetate via the glycine reductase system. This reaction was associated with the formation of ATP.

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“…Proline and glycine are reduced by the enzymes Dproline reductase and glycine reductase (Stadtman, 1956;Stadtman & Elliot, 1956;Tanaka & Stadtman, 1979;Set0 & Stadtman, 1976;Andreesen et al, 1989).…”

Section: Introductionmentioning

confidence: 99%

Proline biosynthesis from L-ornithine in Clostridium sticklandii: purification of Δ1-pyrroline-5-carboxylate reductase, and sequence and expression of the encoding gene, proC

Kenklies¹,

Ziehn²,

Fritsche³

et al. 1999

Microbiology

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Clostridium sticklandii utilizes combinations of amino acids for growth by Stickland reactions. Proline is an efficient electron acceptor in these reactions and is reduced to 5-aminovalerate. Proline can be partly synthesized from ornithine by the action of ornithine aminotransferase and A1-pyrroline-5-carboxylate (PCA) reductase. Both enzymes were present in crude extracts of C. sticklandii in sufficient activity of 0.93 nkat (mg protein)-l and 4 3 nkat (mg protein)'l, respectively, whereas enzymes involved in proline biosynthesis from glutamate were not detected. PCA reductase was purified t o homogeneity in a three-step procedure involving ammonium sulfate precipitation, affinity chromatography with Procion Red and gel filtration on Sephadex GF2OO. The homogeneous enzyme was most likely an octamer of 230 kDa with a subunit size of 25 kDa as obtained by SDS-PAGE and 28.9 kDa as calculated from the sequence. Apparent Km values for PCA and NADH were 019 mM and 0025 mM, respectively. The enzyme also catalysed in vitro the reverse reaction, the oxidation of proline, at alkaline pH values above 8 and higher substrate concentrations (apparent Km values: 1-55 mM for proline and 10-5 mM for NAD at pH 10-0). Studies with growing cells of C. sticklandii and [15N]proline revealed that proline is not oxidized in vivo because 15N was solely detected by HPLC-MS in 5-aminovalerate as the product of proline reduction. The proC gene encoding PCA reductase of C. sticklandii was cloned, sequenced and heterologously expressed in Escherichia coli. The enzyme exhibited high homologies to PCA reductases from different sources. Thus, C. sticklandii is able to synthesize the electron acceptor proline from ornithine (a degradation product of arginine) by action of ornithine aminotransferase and PCA reductase.

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A New Atp-Forming Reaction: The Reductive Deamination of Glycine

Abstract: Novobiocin appears to be the first recorded example of the natural occurrence of a carbamate ester of a sugar derivative.The authors gratefully acknowledge the contributions of Drs.

Cited by 30 publications

References 0 publications

On the Mechanism and Rate of Spontaneous Decomposition of Amino Acids

On the Mechanism and Rate of Spontaneous Decomposition of Amino Acids

Selenium-dependent Growth and Glycine Fermentation by Clostridium purinolyticum

Proline biosynthesis from L-ornithine in Clostridium sticklandii: purification of Δ1-pyrroline-5-carboxylate reductase, and sequence and expression of the encoding gene, proC

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