Glycinal, reaction with succinates

A thioglycoside was immobilized by the following sequence of reactions. Treatment of the dibutyltin acetal of diol 36 with succinic anhydride afforded 37 in an excellent yield of 85%. Attachment of Fmoc protected glycine to TentaGel hydroxyl resin (38, 0.37 mmol/g resin) under standard conditions followed by removal of the Fmoc group by treatment with piperidine gave polymer 27. Compound 37 was immobilized by amide bond formation with 27 in the presence of... 

Fig. 8.7 Plot of log k vs logifc j for the reaction with cyclamH+ of Cu complexes with various ligands L = succinate(l), malonate(2), glycine(3), en(4), ida(5), nta(6), dien(7), and Hedta(8). The curve is calculated using (8.137) with kj, = 1.1 x 10 M" s" and Aq = 2.3 x 10 M. Ref. 296. Reproduced with permission from Y. Wu and T. A. Kaden, Helv. Chim. Acta 68, 1611 (1985).

Fig. 1.8 Asaccharolytic fermentation produces ammonia and short-chain fatty acids. This group of fermentations by oral bacteria utilizes proteins, which are converted to peptides and amino acids. The free amino acids are then deaminated to ammonia in a reaction that converts nicotinamide adenine dinucleotide (NAD) to NADH. For example, alanine is converted to pyruvate and ammonia. The pyruvate is reduced to lactate, and ammonium lactate is excreted into the environment. Unlike lactate from glucose, ammonium lactate is a neutral salt. The common end products in from plaque are ammonium acetate, ammonium propionate, and ammonium butyrate, ammonium salts of short chain fatty acids. For example, glycine is reduced to acetate and ammonia. Cysteine is reduced to propionate, hydrogen sulfide, and ammonia alanine to propionate, water, and ammonia and aspartate to propionate, carbon dioxide, and ammonia. Threonine is reduced to butyrate, water, and ammonia and glutamate is reduced to butyrate, carbon dioxide, and ammonia. Other amino acids are involved in more complicated metabolic reactions that give rise to these short-chain amino acids, sometimes with succinate, another common end product in plaque.

The now classic labeling experiments of Shemin, Rittenberg, and co-workers [39] with glycine, acetate, and succinate led to the recognition that ALA was the first product of the biosynthetic chain of heme. ALA is formed from glycine and succinyl-CoA according to reaction (1). 

An intermediate in the synthesis of porphyrins. It is formed by the condensation of glycine and succinate, a reaction catalysed by the enzyme 6-ALA synthetase. 5-ALA excretion in urine is increased in some types of porphyria and in lead poisoning. 6-ALA can be measured in urine and serum by its reaction with Ehrlich s reagent. 

If a phenol is not indicated, the solution may contain an aliphatic acid. Transfer to a distilling-flask, make definitely acid with dih H2SO4, and distil the volatile formic and acetic acids if present will distil over. If the distillation gives negative reactions, test the residual solution in the flask for oxalic, succinic, lactic, tartaric and citric acids and glycine, remembering that the solution is strongly acid. 

Reactions in which a succinate group derived from a-ketoglutarate condenses with glycine to initiate a succinate glycine cycle have been reviewed by D. Shemin, Federation Proc. 16, 971 (1956). 

But this is not the only entry of glycine into the priming reactions. Glycine can be converted into CO, and water by means of the Shemin cycle, where the catalyst is not oxaloacetate as in the Krebs cycle, but succinate, whose active form, succinyl-CoA, condenses with the ydne. The Shemin cycle can therefore be worked into that of Krebs to form a shunt (Fig. 54). 

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