L-(-)-페닐알라닌

출처Reported found in white bread, macaroni, egg noodles, corn flakes, corn grits, oatmeal, wheat bran, wheat flakes, shredded wheat, barley, brown rice, rye flour, whole grain wheat flour, buttermilk, blue cheese, cheddar cheese, cottage cheese, cream cheese, parmesan cheese, bacon, cured ham, frankfurters, pork sausage, canned red kidney beans, canned sweet corn, canned peas, canned lima beans, canned potatoes, canned asparagus, canned snap beans, canned beets, beef, lamb, fresh ham, veal round, beef liver, chicken, chicken liver, turkey and other natural sources.

용도L-Phenylalanine is an essential amino acid. L-Phenylalanine is biologically converted into L-tyrosine, another one of the DNA-encoded amino acids, which in turn is converted to L-DOPA and further conv erted into dopamine, norepinephrine, and epinephrine. L-Phenylalanine is produced for medical, feed, and nutritional applications such as in the preparation of Aspartame.

일반 설명Odorless white crystalline powder. Slightly bitter taste. pH (1% aqueous solution) 5.4 to 6.

생산 방법In previous large-scale production processes for L-phenylalanine two enzymatic methods were applied: 1. Resolution of N-acetyl-D,L-phenylalanine by carrier-fixed microbial acylase: This process provided pharmaceutical-grade L-phenylalanine, but suffered from the disadvantage that the D-enantiomer had to be racemized and recycled. 2. Stereoselective and enantioselective addition of ammonia to trans-cinnamic acid, catalyzed by L-phenylalanine ammonia lyase (PAL, EC 4.3.1.5): PAL-containing Rhodotorula rubra was used in an industrial process to supply L-phenylalanine for the first production campaign of the sweetener aspartame. When continuously operated in an immobilized whole cell reactor, the bioconversion reached concentration up to 50 g/L Lphenylalanine at a conversion of about 83%. Other processes started from phenylpyruvate with L-aspartic acid as amine donor using immobilized cells of Escherichia coli or from a-acetamidocinnamic acid and immobilized cells of a Corynebacterium equi strain. In both cases L-phenylalanine concentrations up to 30 g/L and more (molar yields as high as at least 98 %) were reached.However, fermentation processes based on glucose-consuming L-phenylalanine overproducing ;mutants of E. coli and coryneform strains turned out to be more economical. L-Phenylalanine is formed in ten enzymatic steps starting from erythrose-4-phosphate and phosphoenolpyruvate. A suitable profile of the specific glucose feed rate prevents acetate formation and leads to improved L-phenylalanine production with a final concentration up to 46 g/L and a corresponding yield of 18 %. L-Phenylalanine is recovered from the fermentation broth either by two-step crystallization or by an ionexchange resin process. The preferred cell separation technique is ultrafiltration; and the filtrates may be treated with activated carbon for further purification. Instead of ion-exchange resins nonpolar, highly porous synthetic adsorbents are recommended to remove impurities. An alternative process in which a cell separator is integrated in the fermentation part, thus allowing cell recycling, was suggested for L-phenylalanine production and may lead to prospective developments.