L-Phenylalanine ammonia

L-Phenylalanine can be synthesised from trims-cinnamic add (Figure A8.12) catalysed by a L-phenylalanine ammonia-lyase from Rhodococcus glutinis. The commercialisation of the process was limited by the low conversion (70%), low stability of the biocatalyst and die severe inhibition exerted by trims-cinnamic add. These problems were largely overcome by researchers at Genex. The process, commercialised for a short period by Gen ex, involves a cell-free preparation of phenylalanine-ammonia-lyase activity from Rhodotorula rubra. 

Maier VP, Hasegawa S (1970) L-Phenylalanine ammonia-lyase activity and naringenin glycoside accumulation in developing grapefruit. Phytochemistry 9 139-144... 

A specialized amino acid residue that serves as an essesn-tial electrophilic center in several enzymatic reactions, including those catalyzed by L-phenylalanine ammonia lyase (Reaction L-phenylalanine tranx-cinnamate + NH3) and L-histidine ammonia lyase (Reaction L-histi-dine urocanate + NH3). The former facilitates the elimination of ammonia and the pro-S hydrogen of phe-nylanine, and the initial step is nucleophilic attack of... 

NT624 Nagai, N., Y. Kojima, M. Shimosaka, and M. Okazaki. Effects of kinetin on L phenylalanine ammonia-lyase ac-tivity in tobacco cell culture. Agr Biol Chem 1988 52(10) 2617-2619. 

Catabolism of histidine in most organisms proceeds via an initial elimination of NH3 to form urocanic acid (Eq. 14-44). The absence of the enzyme L-histidine ammonia-lyase (histidase) causes the genetic disease histidinemia 284/285 A similar reaction is catalyzed by the important plant enzyme L-phenylalanine ammonia-lyase. It eliminates -NH3+ along with the pro-S hydrogen in the (3 position of phenylalanine to form frans-cinnamate (Eq. 14-45). Tyrosine is converted to p-coumarate by the same enzyme. Cinnamate and coumarate are formed in higher plants and are converted into a vast array of derivatives (Box 21-E,... 

Achnine L, Blancaflor EB, Rasmussen S, Dixon RA. 2004. Colocalization of L-phenylalanine ammonia-lyase and cinnamate 4-hydroxylase for metabolic channeling in phenylpropanoid biosynthesis. Plant Cell 16 3098-3109. 

Bolwell, G.P., Bell, J.N., Cramer, C.L., Schuch, W., Lamb, C.J. Dixon, R.A. (1985). L-Phenylalanine ammonia-lyase from Phaseolus vulgaris characterisation and differential induction of multiple forms from elicitor-treated cell suspension cultures. European Journal of Biochemistry 149, 411-19. 

Lawton, M.A., Dixon, R.A. Lamb, C.J. (1980). Elicitor modulation of the turnover of L-phenylalanine ammonia-lyase in French bean suspension cultures. Biochimica et Biophysica Acta 633, 162-75. 

Sewalt, V.J.H., Ni, W., Blount, J.W., Jung, H.G., Masoud, S.A., Howies, P.A., Lamb, C. and Dixon, R.A. (1997) Reduced lignin content and altered lignin composition in transgenic tobacco down-regulated in expression of L-phenylalanine ammonia-lyase or cinnamate 4-hydroxylase. Plant Physiol., 115,41-50. 

L-Phenylalanine ammonia lyase (PAL EC 4.3.1.5), an enzyme found in a variety of plants, catalyzes both the deamination of L-phenylalanine to (L )-3-phenyl-2-butenoic acid and the reverse reaction33-36. 

S. Yamada, K. Nabe, N. Izuo, K. Nakamichi, and I. Chibata, Production of L-phenylalanine from trans-dnnamic add with Rhodotorula glutinis containing L-phenylalanine ammonia-lyase activity, Appi. Enuiron. Microbid., 42 773 (1981). 

Fig. 15 L-Phenylalanine production using an L-phenylalanine ammonia lyase.

The biocatalytic addition of ammonia to trans-cinnamic acid, 28, proceeds enantio-selectively in the presence of whole-cells containing L-phenylalanine ammonia lyase. Of the suitable strains, wild-type strains of Rhodococcus rubra as well as Rhodotorula rubra were found to be very efficient. The biotransformation is carried out in basic media at pH 10.6. In addition, analogous reactions furnishing non-natural substituted derivatives of L-phenylalanine starting from substituted trans-cinnamic acid derivatives were reported by Mitsui, and Great Lakes, respectively [38 c]. 

M. Yanaka, D. Ura, A. Takahashi, N. Fukuhara, Manufacture of -Substituted Alanines with L-Phenylalanine Ammonia-Lyase, Mitsui Toatsu Chemicals, 1992, JP 06113870. 

Use Simple esters of ( )-C. a. are used as odor and taste additives in perfumes and foods. Esters of C. a. and p-methoxy-C. a. are used as sun blockers. Biosynth. By elimination of ammonia from L- phen-ylalanine, catalyzed by L-phenylalanine ammonia lyase (PAL, EC 4.3.1.5). 

K. Szkutnicka and S. Lewak, Stimulation of L-phenylalanine ammonia-lyase (PAL) activity by D-phenylalanine in germinating seeds. Plant Science Letters 5, 1 7 (1975). 

Phenylalanine is converted to cinnamic acid by the action of the ubiquitous enzyme L-phenylalanine ammonia lyase (PAL) (EC 4.3.11.5) (Davin et al., 1992 Hanson and Havir, 1981). This enzyme, which catalyzes loss of ammonia and production of -cinnamic acid (1), has been detected in a large number of vascular plants and several genera of basidi-omycetes. PAL occurs mainly in the cytoplasm, but some plants contain low levels of PAL in plastids, mitochondria, and microbodies (Hanson and Havir, 1981). Cinnamate is produced by the action of PAL in an elimination reaction... 

In a related fashion, asymmetric amination of ( )-cinnamic acid yields L-phenylalanine using L-phenylalanine ammonia lyase [EC 4,3,1,5] at a capacity of 10,000 t/year [1274, 1601], A fascinating variant of this biotransformation consists in the use of phenylalanine aminomutase from Taxus chinensis (yew tree), which interconverts ot- to p-phenylalanine in the biochemical route leading to the side chain of taxol [1602], In contrast to the majority of the cofactor-independent C-0 and C-N lyases discussed above, its activity depends on the protein-derived internal cofactor 5-methylene-3,5-dihydroimidazol-4-one (MIO) [1603], Since the reversible a,p-isomerization proceeds via ( )-cinnamic acid as achiral intermediate, the latter can be used as substrate for the amination reaction. Most remarkably, the ratio of a- vs, 3-amino acid produced (which is 1 1 for the natural substrate, R = H) strongly depends on the type and the position of substituents on the aryl moiety While o-substituents favor the formation of a-phenylalanine derivatives, / -substituted substrates predominantly lead to p-amino analogs, A gradual switch between both pathways occurred with m-substituted compounds. With few exceptions, the stereoselectivity remained exceUent (Scheme 2,215) [1604, 1605],... 

Biosynthesis. The primary precursors of L. are con-iferyl, sinapyl and p-coumaiyl alcohoi, which are derived from 4-hydroxycinnamic acid. L. from conifers (i. e. from softwood) is derived chiefly from conifeiyl alcohol with variable but small proportions of sinapyl and p-coumaryl alcohol. L. from dicotyledonous an-giosperms (i.e. from hardwood), particularly deciduous trees, is formed chiefly from sinapyl (-44%) and coniferyl (-48 %) alcohol, with about 8 % p-cou-maryl alcohol. L. in grasses is formed from p-coumar-yl (-30%), coniferyl (-50%) and sinapyl (-20%) alcohol. These primary L. precursors are formed from the aromatic amino acids L-phenylalanine and L-tyro-sine by a series of reactions shown (Rg.). The first reaction is catalysed by L-Phenylalanine ammonia-lyase (EC 4.3.1.5) (see) this enzyme is induced by light in a process involving phytochrome, and it is of general importance in the synthesis of plant phenolic compounds from phenylalanine and tyrosine. 

Phenolic Content and L-Phenylalanine Ammonia-Lyase Activity in Peach Fruit... 

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