The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 
 
 

Enzymatic modification of tryptophan residues by tryptophan side chain oxidase I and II from Pseudomonas.

The enzymatic modification of tryptophan residues in Trp-Leu, Leu-Trp, Leu-Trp-Leu, and yeast mating hormone (alpha-factor), a tridecapeptide containing Trp-1 and Trp-3, has been investigated with tryptophan side chain oxidase I crystallized previously from Pseudomonas and tryptophan side chain oxidase II recently isolated from the same organism. With Trp-Leu as substrate, threo- and erythro-beta-hydroxytryptophan residues were identified as primary products and the former perferentially underwent second step dehydrogenation to give beta-ketotryptophan. Free threo- and erythro-beta-hydroxytryptophan, hitherto undescribed tryptophan derivatives, were isolated after enzymatic hydrolysis, identified, and characterized. Leu-alpha, beta-dehydrotryptamine, a new biochemical entity, was a sole main product of Leu-Trp. With Leu-Trp-Leu, diastereoisomeric Leu-beta-hydroxyl-Trp-Leu and Leu-alpha, beta-dehydro-Trp-Leu were formed simultaneously, the pH and ionic strength being determinants of the ratio of these products. Leu-threo-beta-hydroxy-Trp-Leu was also converted to Leu-beta-keto-Trp-Leu, but, distinct from NH2-terminal beta-hydroxytryptophan, both diastereoisomers underwent acid-catalyzed dehydration to give Leu-alpha, beta-dehydro-Trp-Leu. Thus, the mode of modification was shown to be prescribed by the site of tryptophan in peptides and the results were the same with either tryptophan side chain oxidase I or II, except that the latter was almost inactive on Trp-Leu. With any substrate, 3-indolecarboxaldehyde was a sole detectable by-product.[1]

References

  1. Enzymatic modification of tryptophan residues by tryptophan side chain oxidase I and II from Pseudomonas. Ito, S., Takai, K., Tokuyama, T., Hayaishi, O. J. Biol. Chem. (1981) [Pubmed]
 
WikiGenes - Universities