Tyrosine microbial

Phenoxazines — The two main types of phenoxazines are the ommochromes and the microbial phenoxazines. The biosynthesis of ommochromes occurs via the kynurenine pathway. The tryptophan amino acid is converted to formylkynurenine and then to kynurenine and 3-hydroxykynurenine. Not all the steps of ommochrome synthesis are completely elucidated yet. Ommatins are dimers and ommins are oligomers of 3-hydroxykynurenine. - The papiliochromes are derived from tyrosine as well as from the tryptophan pathway. The key intermediate in the formation of papiliochromes is N-beta-alanyldopamine (NBAD). Papiliochromes are synthesized in special wing scale cells, before melanins. " "... 

Kittelman, M. Oberer, L. Blum, W. Ghisalba, O. (1999) Microbial hydroxylation and simultaneous formation of the 4"-0-methylglucoside of the tyrosine-kinase inhibitor CGP 62706. Chimia, 53, 594-6. 

In the microbial transformations, it is possible to use several kinds of synthetase in the case of some materials which have no reaction site modified by fluorine ). For instance, tyrosine phenollyase ( -tyrosinase, EC 4.1.99.2) afforded... 

Microbial Catabolism of Phenylalanine, Tyrosine, and Other Aromatic Compounds... 

Conversion of the Microbially Produced Preadhesive to an Adhesive Protein. The polyphenolic protein purified from yeast adheres to a wide variety of surfaces including glass and plastic. The adherence probably results from the presence of many polar residues capable of hydrogen bonding and lysine residues that can form ionic interactions. However, this protein does not generate water-resistant bonds to surfaces nor does it have cohesive strength. For those purposes, it is necessary to convert at least a portion of the tyrosine residues to dopa and permit crosslink formation to occur after surface adhesion is achieved. That is, it is necessary to mimic the natural mussel process in which the dopa form of the polyphenolic protein is applied and then rapidly... 

The microbial product staurosporine is a non.sclcciivepav tcin tyrosine kinase inhibitor uf EGFR kinase. A simpitt dianilinuphthalimide. analogue I. is a potent and sclcctlw inhibitor of EGFR kina.se.- ... 

Indolmydn.—Previous evidence on the biosynthesis of indolmycin (88) in Strepto-myces griseus cultures accords with the pathway shown in Scheme 4. The first two steps in the pathway have been carried out using cell-free extracts of 5. griseus - and recent work has led to the isolation of two enzymes which can effect these transformations. The first, tryptophan transaminase, catalysed the pyridoxal phosphate-dependent transamination of L-tryptophan, but not D-trptophan, and in common with some other microbial transaminases, a-ketoglutarate was an efficient amino-group acceptor. L-Phenylalanine, tyrosine, and 3-methyltryptophan (this compound inhibited enzyme function) also underwent transamination. 

The shikimate pathway of aromatic acid biosynthesis is the source of building blocks for a very wide number of natural products from microbial and plant kingdoms. Remarkably, it appears that this pathway is the unique source for the de novo synthesis of phenylalanine, tyrosine, and tryptophan. Although many shikimate-derived... 

The structures and properties of quinone methides were recently reviewed . Inter alia, the microbial tyrosine phenol lyase (TPL) catalyzes the a, /3-elimination of L-tyrosine to phenol and ammonium pyruvate. It is assumed that the process includes three steps, the second of which is tautomerization of the aromatic moiety which converts it into a good leaving group (equation 49) °. 

Oxidations - Enzymes which functionalize inactivated carbon are often difficult to obtain and handle. Many examples exist of oxidations using microbial fermentations, e.g. for steroids, and recently in olefin oxidation.Such preparative transformations have not been achieved with purified enzymes and are unlikely to be amenable to large-scale in vitro approaches because of instability and complexity of the enzyme systems. Klibanov and coworkers, however, have developed systems with horseradish peroxidase and xanthine oxidase for oxidation of aromatic alcohols and amines, for use in syntheses and waste water treatment. Hydroxyphenyl compounds can be oxidized to dihydroxy derivatives. L-DOPA has been made from L-tyrosine in this manner.Cyclohexanone was oxidized to t-caprolactone with a bacterial oxygenase. 

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