Lysine pathway

Vogel HJ Distribution of lysine pathways among fungj Evolutionary implication. Am Nat 1964 98 435 46. 

L-Saccharopine. N-(5-Amino-5-carboxypemyt)-L-glutamic acid -Af-(L-glutar-2-yl)-L-lysine. CnH NjO. mol wt 276.29. C 47.82%. H 7.30%, N 10.14%, O 34.75%. A lysine precursor in the aminoadipic add-lysine pathway in yeast Darling. Larsen, Acta Chem. Scand. IS, 743 (1961) Kjaer. Larsen, ibid. 750 Kuo et al. Biochem Biophys. Res. Commun. 8, 227 (1962) Trupin, Broquist, J. Biol Chem. 240, 2524 (1965) Jones, Broquist, ibid. 241, 3430 sqq. (1966). Isoln from mycelium of the yeast Candida utilis Marimoto, Yamano, Biochem. Z. 340, 155 (1964). 

A careful repetition of this early experiment on biosynthetic origins by Finalayson and Simpson served to confirm that the wish had been father to the thought. Actually, the thought did have considerable merit since as it turned out, the lysine pathway does... 

Auxotrophic mutants are used in the production of end products of branched pathways, ie pathways leading to more than one amino add at the same time. This is the case for L-lysine, L-methicmine, L-threonine and L-isoleudne in Brevibacterium flavum and Corynebacterium glutamicum. 

Revelles O, M Espinosa-Urgel, T Euhrer, U Sauer, JL Ramos (2005) Multiple and interconnected pathways for L-lysine catabolism in Pseudomonas putida KT2440. J Bacteriol 187 7500-7510. 

Revelles O, M Espinosa-Urgel, S Molin, JL Ramos (2004) The davDT operon of Pseudomonas putida, involved in lysine catabolism, is induced in response to the pathway intermediate 5-aminovaleric acid. J Bacterial 186 3439-3446. 

Three compounds acetoacetate, P-hydroxybutyrate, and acetone, are known as ketone bodies. They are suboxidized metabolic intermediates, chiefly those of fatty acids and of the carbon skeletons of the so-called ketogenic amino acids (leucine, isoleucine, lysine, phenylalanine, tyrosine, and tryptophan). The ketone body production, or ketogenesis, is effected in the hepatic mitochondria (in other tissues, ketogenesis is inoperative). Two pathways are possible for ketogenesis. The more active of the two is the hydroxymethyl glutarate cycle which is named after the key intermediate involved in this cycle. The other one is the deacylase cycle. In activity, this cycle is inferior to the former one. Acetyl-CoA is the starting compound for the biosynthesis of ketone bodies. 

The question of the stability of the biomolecules is a vital one. Could they really have survived the tremendous energies which would have been set free (in the form of shock waves and/or heat) on the impact of a meteorite Blank et al. (2000) developed a special technique to try and answer this question. They used an 80-mm cannon to produce the shock waves the shocked solution contained the two amino acids lysine and norvaline, which had been found in the Murchison meteorite. Small amounts of the amino acids survived the bombardment , lysine seeming to be a little more robust. In other experiments, the amino acids aminobutyric acid, proline and phenylalanine were subjected to shock waves the first of the three was most stable, the last the most reactive. The products included amino acid dimers as well as cyclic diketopiperazine. The kinetic behaviour of the amino acids differs pressure seems to have a greater effect on the reaction pathway than temperature. As had been recognized earlier, the effect of pressure would have slowed down certain decomposition reactions, such as pyrolysis and decarboxylation (Blank et al., 2001). 

Fig. 6. The metabolic pathway for lysine biosynthesis in Escherichia coli, which contains a missing enzyme that is not found in the genome.

Penicillins and cephalosporins bind irreversibly to serum albumin. It has been shown that drug-protein conjugates result from the aminolysis of the /3-lactam bond by the e-amino group of lysine residues in the protein (Fig. 5.1, Pathway e). The bound penicilloyl group appears to be the major antigenic determinant of penicillin allergy [145-148],... 

C-Flanking serine or cysteine residues can increase the rate of deamidation and, particularly, cleavage, in analogy with the mechanism discussed for aspartic acid [92], Increased reactivity can also result from the presence of a C-flanking histidine, which increases the nucleophilicity of the Asn side-chain amido group and, thus, favors Pathways f and perhaps d in Fig. 6.29 [124], N-Flanking lysine was also found to facilitate Pathway e (Fig. 6.29) in a pH-dependent maimer, likely by increasing the electrophilicity of the carbonyl C-atom in the Asn side chain [125]. 

Cleavage of the oxirane C-0 bond produces a zwitterionic intermediate (Fig. 10.22), which that can undergo chloride shift (Pathway a) to 2,2-dich-loroacetyl chloride (10.90) followed by hydrolysis to 2,2-dichloroacetic acid (10.91). Furthermore, the zwitterionic intermediate reacts with H20 or H30+ (Pathway b) by pH-independent or a H30+-dependent hydrolysis, respectively. The pH-independent pathway only is shown in Fig. 10.22, Pathway b, but the mechanism of the H30+-dependent hydrolysis is comparable. Hydration and loss of Cl, thus, leads to glyoxylyl chloride (10.92), a reactive acyl chloride that is detoxified by H20 to glyoxylic acid (10.93), breaks down to formic acid and carbon monoxide, or reacts with lysine residues to form adducts with proteins and cytochrome P450 [157], There is also evidence for reaction with phosphatidylethanolamine in the membrane. 

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