I.-Threonine

An estimation of the amount of amino acid production and the production methods are shown ia Table 11. About 340,000 t/yr of L-glutamic acid, principally as its monosodium salt, are manufactured ia the world, about 85% ia the Asian area. The demand for DL-methionine and L-lysiae as feed supplements varies considerably depending on such factors as the soybean harvest ia the United States and the anchovy catch ia Pern. Because of the actions of D-amiao acid oxidase and i.-amino acid transamiaase ia the animal body (156), the D-form of methionine is as equally nutritive as the L-form, so that DL-methionine which is iaexpensively produced by chemical synthesis is primarily used as a feed supplement. In the United States the methionine hydroxy analogue is partially used ia place of methionine. The consumption of L-lysiae has iacreased ia recent years. The world consumption tripled from 35,000 t ia 1982 to 100,000 t ia 1987 (214). Current world consumption of L-tryptophan and i.-threonine are several tens to hundreds of tons. The demand for L-phenylalanine as the raw material for the synthesis of aspartame has been increasing markedly. 

Thus when proposals were being considered for the nomenclature of the amino acids, Rose 12) agreed to modify the term d (—) threonine he had suggested to show the connection with D-threose to i>threonine, in conformity with the rulings proposed for the other amino acids. 

The polymyxins—The members of the polymyxin group have very similar chemical and physical properties. They are all cyclic basic polypeptides containing characteristic constituents such as a,y-diaminobutyric acid, i,-threonine and a fatty acid. They differ by the presence or absence of the additional amino acids D-leucine, L-leucine, L-isoleucine, n-phenylalanine, D-valine and D-serine, as well as by the nature of the fatty acid Table 1.11). Their molecular weights are aU in the region of 1,200. Although several structural features had been established very early - the exact... 

N-(9-Fluorenylmethoxycarbonyl-0-(3,4,6-tri-0-acetyl-2-azido-2-deoxy-a-D-galactopyranosyl)-i -threonine teit-Butyl Ester 20 [34]... 

The PRP-1 column also has been used successfully in the HPLC assay of several key aztreonam intermediates. The carbobenzoxy-L-threoninamlde (CBZ-I,-threoninamide) was one. It was the first major intermediate isolated in the synthesis of aztreonam starting from I -threonine. The synthetic sequence is depicted in Figure 6. Two major impurities were benzyl alcohol and benzyl carbamate the former produced by the hydrolysis of benzyl chloroformate and the latter by the reaction between benzyl chloroformate and ammonia. The purpose... 

Figure 7. HPLC of CBZ-I -threoninainide. Column PRP-1 (15 x 4.1 mm i.d., 30°C). Mobile phase 60% methanol - 40% water - 0.05M ammonium sulfate. Flow rate 1 ml/min. Detection UV 215 nm. Peaks (1) = I.-threonine, (2) = CBZ-L-threonine, (3) = CBZ- -threoninamide, (4) benzyl alcohol, (5) = benzyl carbamate.

Figure 15. Structure of CBZ- -azetldlnone-TBA salt and related compounds derived from I -threonine.

Pharmaceutical grade L-lysine monohydrochroride,L-arginine, L-citruline, L-valine leucine, L-isoleucine, L-tryptophan,L-tyrosine,DL-methionine,L-glutamic acid,L-asparticacid, I alanine, glycin e, I threonine, L-serine, L-proline, L-glutamine, I systeine, and sodium sulfate anhydrate were used. 

Lysine plus threonine severely inhibits growth of maize in a synergistic manner. Growth inhibition could result from combined effects of lysine on aspartate kinase and threonine on homoserine dehydrogenase, resulting in starvation for methionine. Growth inhibition by lysine -i- threonine can be overcome by supplying methionine. Bryan [1980) Miflin [1977). 

In the domino Michael/alkylation reaction applied to the synthesis of 3-(2H)-furanones, the ethyl 4-bromoacetoacetate 203 and nitrostyrene 204 were first trialed with a range of catalysts. In this instance, the so-called modified Feist Binary reaction was completed with an I-threonine bifunctional tertiary amine/thiourea catalyst 205 to produce the furanone 206 in excellent yield and high enantioselec-tivity (Scheme 7.42) [107]. In another report, the furan ring as part of other bicyclic or tricyclic systems was also prepared through an enantioselective Michael addi-tion/nucleophilic substitution reaction (Scheme 7.43) [108]. When diketones and ( )-P,P-bromonitrostyrenes 207 were stirred, again with a bifunctional thiourea... 

Komatsubara S, Kisumi M, Murata K, Chibata I. Threonine production by regulatory mutants of Serratia marcescens. Appl Environ Microbiol 1978 35 834-40. 

Type I threonine-rich fish antifreeze protein [528]... 

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