Studies on Diastereoisomeric α-Amino Acids and Corresponding α-Hydroxy Acids. VII. Influence of β-Configuration on Enzymic Susceptibility

Winitz, Milton; Bloch-Frankenthal, Leah; Izumiya, Nobuo; Birnbaum, Sanford M.; Baker, Carl; Greenstein, Jesse P.

doi:10.1021/ja01592a022

Cited by 139 publications

(45 citation statements)

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“…Thus, the a-hydroxy and a-keto compounds are comparable as substitutes for valine. a-Hydroxyisovaleric acid, readily synthesized from valine by reaction with nitrous acid (17), is less costly than. the keto analogue ($0.70 vs. $2.50/g in present syntheses).…”

Section: Resultsmentioning

confidence: 99%

Utilization of α-Keto and α-Hydroxy Analogues of Valine by the Growing Rat

Chawla¹,

Rudman²

1974

J. Clin. Invest.

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A B S T R A C T When 70-80-g male albino rats eat a diet furnishing daily requirement of valine for optimal growth (70 iumol/g) and all other nutrients ("complete diet"), they gain weight at an average rate of 3.0 g/100 g body wt/day. When valine is removed, they lose weight at an average 2.1 g/100 g body wt/day. The growth retardation is improved or corrected by adding valine to the diet, daily weight gain being proportional to dietary valine content over a range of 0-70 /%mol/g.Addition of a-ketoisovaleric acid instead of valine to the valine-free diet also improves or corrects the growth failure. Percent efficiency of a-ketoisovaleric acid as a substitute for valine was calculated as: 100 X (micromole valine per gram diet required to produce specified growth response)/(micromole a-ketoisovaleric acid per gram diet required to produce the same response). Efficiency of the substitution is inversely related to dietary content of the keto analogue, being 80% when diet contains 17.5 iumol/g (molar equivalent of I the daily requirement of valine), and 37% when diet provides 140 .mol/g (molar equivalent of twice the daily requirement of valine).a-Hydroxyisovaleric acid also substitutes for valine.Efficiency of the substitution at the single ration tested, 70 Amol/g diet, is 45%, similar to that for the keto analogue under the same conditions.When [1-"C]a-ketoisovaleric acid is injected intravenously, 30-80% of the administered radioactivity is exhaled as 14CO2 within 24 h. This finding suggests that inefficiency of a-ketoisovaleric acid as a substitute for valine results in part from degradation of the keto acid to isobutyric acid by branched chain dehydrogenasedecarboxylase.Oral administration of neomycin, polymyxin, and bacitracin reduces efficiency of a-ketoisovaleric acid as a substitute for valine by -. This effect suggests that

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Section: Resultsmentioning

confidence: 99%

Utilization of α-Keto and α-Hydroxy Analogues of Valine by the Growing Rat

Chawla¹,

Rudman²

1974

J. Clin. Invest.

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“…The dipeptides were prepared by coupling of the benzyloxycarbonyl amino acid and amino acid methyl ester using dicyclohexylcarbodiimide according to conventional procedures (13). Saponification and hydrogenation yielded the free dipeptides having the following physical constants: glycyl-L-phenylalanine, [aIDz5 +40.0°, c 2, water (lit.…”

Section: Methodsmentioning

confidence: 99%

Peptide Conformations. I. Nuclear Magnetic Resonance Study of the Carbamate Reaction of Amino Acids and Peptides

Lemieux¹,

Barton²

1971

Can. J. Chem.

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Nuclear magnetic resonance spectroscopy has been applied to the study of carbamate formation in solutions of amino acids and peptides in a carbonate-bicarbonate system. The possible conformations of these carbamates are discussed in terms of the n.m.r. data obtained. The n.m.r. parameters are reported for the diastereomers L-alanyl-L or D-phenylalanine and L-phenylalanyl-L or D-alanine and for the dipeptide glycyl-L-phenylalanine and their carbamates. The results are interpreted in terms of preferred rotamers about the C.-CD bond of the phenylalanine residue and a p-type conformation of the peptide chain, wherein the two a-protons lie in the plane of the amide bond. All observations are in agreement with a shorter end to end distance in L,D-compared with L,L-dipeptides.

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“…Methyl (2R,3S)-2-hydroxy-3-methylpentanoate (Mamer, 2000;Winitz et al, 1956): D-allo-isoleucine (65 mg, 0.5 mmol) was dissolved at 5 1C in a mixture of 0.5 ml 1N HCl, 2 ml of water, and 1 ml of acetic acid. A solution of sodium nitrite (350 mg, 5 mmol) in 0.6 ml of water was added dropwise and the resulting solution was stirred over night at 51C.…”

Section: Synthesis Of Necic Acids and Their Methyl Estersmentioning

confidence: 99%