Heat Capacities of N-Acetyl Amides of Glycine, L-Alanine, L-Valine, L-Isoleucine, and L-Leucine

Conformational properties of N-acetyl-L-alanine N',N'-dimethylamide.

Ab initio/DFT analysis of the conformational properties of free Ac-Ala-NMe(2) (N-acetyl-L-alanine-N',N'-dimethylamide) in terms of the N-H.O, N-H.N, C-H.O hydrogen bonds and C(delta+) = O(delta-) dipole attractions was performed. The Ala residue combined with the C-terminal tertiary amide prefers an extended conformation and that characteristic of the (i + 1)th position of the betaVIb turn. The...

Diagnosis of maple syrup urine disease by determination of L-valine, L-isoleucine, L-leucine and L-phenylalanine in neonatal blood spots by gas chromatography-mass spectrometry.

A novel method was developed for the diagnosis of maple syrup urine disease (MSUD) by the determination of L-valine, L-leucine, L-isoleucine and L-phenylalanine in dried blood spots of newborns by gas chromatography-mass spectrometry (GC-MS). The four amino acids were extracted from blood samples by methanol and derivatized by n-butanol and trifluroacetic anhydride under optimum reaction condit...

Effect of urea on the optical rotatory dispersion of diketopiperazines of L-serine, L-alanine, L-lysine, L-valine, and L-valylglycine.

Diauxie used as a microbiological assay for L-isoleucine or L-valine in Escherichia coli.

FIG. 1. Diauxic lag of cuiltures conitaining valine and isoleucine. All cultures were grown by shakinig (330 rev/ min) at 37 C in medium containing 2.0 g ofNaH2PO4 O H20, 7.0 g ofK2HP04, 2.0 g of (NH4)2SO4, 0.2 g of MgSO4 v 7H20 and I mg of thiamine hydrochloride in I liter of distilled water. Overnight cultures grown in 0.2%o glucose were harvested by centrifugation during exponential phase, r...

THE CONDUCTIVITIES OF AQUEOUS SOLUTIONS OF GLYCINE, d,l-VALINE, AND l-ASPARAGINE

1. The conductivities of aqueous solutions of glycine, d,l-valine, and l-asparagine have been determined, and comparisons have been made with similar data reported in the literature. 2. On the basis of certain theoretical considerations, calculations of the expected conductivities of aqueous solutions of glycine, asparagine, aspartic acid, and glutamic acid have been made and these data have be...