Isoleucine manufacture

There are 22 different AAs in the body of the bird, 10 of which are essential AA (EAA arginine, methionine, histidine, phenylalanine, isoleucine, leucine, lysine, threonine, tryptophan and valine), i.e. cannot be manufactured by the body and must be derived from the diet. Cystine and tyrosine are semi-essential in that they can be synthesized from methionine and phenyla-... 

Although all of the amino acids listed in Table SO-1 are present in the proteins of the human body, not all of them need to be in the food. Experiments have been carried out which show that nine of the amino acids are essential to man. 1 hese nine essential amino acids are histidine, lysine, tryptophan, phenylalanine, leucine, isoleucine, threonine, methionine, and valine. The human body seems to be able to manufacture the others, which are called the non-essential amino acids. Some organisms that we usually consider to be simpler than man have greater powers than the human organism, in that they are able to manufacture all of the amino acids from inorganic constituents. The red bread mold, Neurospora, has this power. 

Amyl alcohols occur in eight isomeric forms and have the empirical formula CjHnOH. All are liquids at ambient conditions except 2,2-dimethylpropanol (neopentyl alcohol), which is a solid. Almost all amyl alcohols are manufactured in the United States by the hydroformylation of butylenes. Yeast fermentation processes for ethanol yield small amounts of 4-methyl-l-butanol (isoamyl alcohol) and 2-methyl-1-butanol (active amyl alcohol, scc-butyl-carbinol) as fusel oil. However, when the amino acids leucine and isoleucine are added to sugar fermentations by yeast, 87% and 80% yields of 4-methyl-l-butanol and 2-methyl-l-butanol, respectively, are obtained (Fieser and Fieser, 1950). These reactions are not suitable for commercial applications because of cost, but they do indicate the close structural relationship between these C5 amino acids and the C5 alcohols. The reactions occur under nitrogen-deficient conditions. If a nitrogen source is readily available, the production of the alcohols is lowered considerably. 

The liver uses alanine, along with serine, to manufacture glucose. Phenylalanine, glycine and proline levels are not affected to any greater extent than that seen in other tissues. The concentrations of the branched chain amino acids isoleucine and valine in blood remain unchanged. 

Herbicidal sulfonylureas have a unique mode of action they interfere with a key enzyme required for plant cell growth - acetohydroxyacid synthase (AHAS, EC 2.2.1.6) [1, 2, 3] (see also Mark E. Thompson in this volume, Chapter 2.1 Biochemistry of the Target and Resistance ). AHAS is the enzyme responsible for the synthesis of the branched-chain amino acids valine, leucine and isoleucine. Inhibition of this enzyme disrupts the plant s ability to manufacture proteins, and this disruption subsequently leads to the cessation of all cell division and eventual death of the plant. 

Degussa/Rexim, partly in collaboration with Chinese manufacturers, produce (L)-threonine, (L)-valine and (L)-isoleucine by fermentation. [62] With genetically modified strains from Echerichia coli and Serratia marcescens, they are able to achieve end concentrations of 100 grams per litre. 

In addition to the amino acid derived amino alcohols mentioned above, two other amino alcohols have been widely used ( R, 25)-ephedrine (8) which is a naturally occurring plant alkaloid, and the (5, 5)-amino diol (9) which is produced microbiologically as a byproduct from the manufacture of the antibiotic chloramphenicol. Note the presence of two adjacent [or contiguous] stereogenic centres in both these molecules, a useful feature also present in two of the amino acids, (5,5)-isoleucine (10) and (25,3/ )-threonine (11). The (/ )-amino alcohol (12) is also readily available in enantiomerically pure form. 

D-hydroxyphenylglycine, L-hydroxyproKne, L-isoleucine, L-lysine, L-ornithine, L-phenylalanine, o-phenylglycine, L-polylysine, L-proline, L-serine, L-threonine, L-tryptophan, and L-tyrosine) was investigated and successfully manufactured on an industrial scale. Glycine is produced by chemical methods because the molecule has no chiral center, and methionine is also produced by chemical methods in its racemic form because the main use of the amino acid is as feedstuff. o-Methionine is metabolized in animals by the action of D-amino acid oxidase. These amino acids were useful as sources of medicines, food additives, feed-stuffs, and starting materials for chemical synthesis. 

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