Formation of amino acids on heating glycine with alumina

The conversion of glycine into amino acids on heating at 240°C with basic manganous carbonate and alumina is investigated. Alanine, -aminobutyric acid, norvaline, norleucine, sarcosine, N-ethylglycine, N-methylalanine, N-ethylalanine, aspartic acid and glutamic acid are identified among the products of the reaction. Paper chromatography, ion-exchange chromatography and nuclear magnetic resonance are used for the analysis. A scheme for the observed transformations is presented and it is suggested that it may have been a pathway for the synthesis of amino acids from glycine under primitive Earth conditions.     

Reduction of acute alcoholic intoxication by alpha amino acids: glycine and serine

The ability of glycine and of serine to protect rats from ethanol induced motor impairment was determined by pretreating the animals with these drugs, administering ethanol 30 minutes later, and evaluating the rats' performance on a rotor-rod test at 30 minutes and 2 hours post-ethanol. Performance of the glycine and serine-pretreated rats was significantly superior to that of controls at the 30-minute post-ethanol trial, but not at the 2-hour trial. Blood-alcohol levels measured at the times of the trials corresponded with the behavioral performance. The levels were significantly depressed during the 30-minute post-ethanol trials for both the glycine and serine-pretreated groups. These findings provide evidence that glycine and serine-induced protection against the described motor impairments caused by ethanol may be due to a suppression of the rate of absorption of ethanol from the gastrointestinal tract.     

Heat inactivation of threonine,glycine, and the acidic amino acids

A method has been evolved for the quantitative codetermination of resazurin and resorufin. Examples of its use with erythrocytes and with succinic dehydrogenase of rat liver are presented.     

Effects of amino acids and α-amanitin on bovine embryo development in a simple protein-Free medium

Five experiments, utilizing 3741 embryos produced in vitro, were designed to test the effects of Eagle's nonessential amino acids, and combinations of Eagle's essential amino acids and the RNA polymerase inhibitor α-amanitin on the development of preimplantation bovine embryos in a modified protein-free KSOM medium. Embryos were cultured in 5% O₂:5% CO₂:90% N₂ at 39°C for the first 40–44 hr in modified KSOM, and embryos with ≥4 cells were cultured in modified KSOM-PVA with different amino acids in experiments 1–4, and with the addition of α-amanitin in experiment 5. In experiment 1, addition of 0.5× of the essential amino acids, with different concentrations of nonessential amino acids significantly increased hatching of blastocysts and decreased blastocyst degeneration, but increasing the nonessential amino acids from 1× to 5×, did not stimulate embryo development. In experiments 2–4, increasing only the glycine concentration, or adding each of the 12 essential amino acids singly or several in combination to the medium containing nonessential amino acids, did not significantly improve embryo development. Taurine (0.4 mM) in the modified KSOM medium reduced blastocyst degeneration. In experiment 5, α-amanitin (20 μM) completely inhibited further embryo development when it was added at several stages from 4-cell embryos to morulae. The study with protein-free KSOM plus amino acids provided a completely defined simple medium for culturing bovine embryos, with evidence that continuous mRNA activity and presumed protein synthesis was obligatory to meet the complex and continuous requirements for proteins by the developing blastocyst. Mol. Reprod. Dev. 46:278–285, 1997. © 1997 Wiley-Liss, Inc.     

Metabolism of peptide amino acids by Chinese hamster ovary cells grown in a complex medium

Metabolic flux analysis is a useful tool for unraveling relationships between metabolism and cell function. Material balancing can be used to provide estimates of major metabolic pathway fluxes, provided all significant metabolite uptake and production rates are measured. Potential sources of metabolizable material in many serum-free media formulations are low molecular weight digests of biological material such as yeast extracts and plant or animal tissue hydrolysates. These digests typically contain large amounts of peptides, which may be utilized as amino acids. This article demonstrates the need for accounting for amino acids liberated from peptides in order to accurately estimate pathway fluxes in Chinese hamster ovary cells grown in a complex (hydrolysate containing) medium. A simplified model of central carbon metabolism provides the framework for analyzing external metabolite measurements. Redundant measurements are included to ensure the consistency of data and assumed biochemistry by comparing redundant measurements with their predicted values from a minimum data set, and by expressing the degree of agreement using a statistical "consistency index." The consistency index tests whether redundancies are satisfied within expected experimental error. For chemostat steady states of CHO cultures grown in a hydrolysate-supplemented medium, consistent data were obtained only when amino acids liberated from peptides were taken into account.