Tryptophan tryptophylquinone dehydrogenase

Conversion of methanol into formaldehyde by methanol dehydrogenase. A complex array of genes is involved in this oxidation and the dehydrogenase contains pyrroloquinoline quinone (PQQ) as a cofactor (references in Ramamoorthi and Lidstrom 1995). Details of its function must, however, differ from that of methylamine dehydrogenase that also contains a quinoprotein—tryptophan tryptophylquinone (TTQ). 

Methylamine dehydrogenase of Methylophilus methylotro-phus, proton transfer from the methylamine adduct of tryptophan tryptophylquinone (TTQ) CHs-amine vs. CDs-amine, transient kinetics studies of H-transfer step, H/D IE 5-40 °C, Ah/Ad = 16.8 0.5, AH 42.2 1.1 (H), 43.2 1.8 (D) kJ/mol, rate constant unchanged. 

This enzyme [EC 1.4.99.3], also known as amine dehydrogenase and primary-amine dehydrogenase, catalyzes the reaction of R-CH2-NH2 with water and an acceptor to produce R-CHO, ammonia, and the reduced acceptor. Tryptophan tryptophylquinone (TTQ) is the cofactor for this enzyme. See Resonance Raman Spectroscopy Topaquinone... 

Fig. 6. Electron transfer complex between methylamine dehydrogenase and amicyanin from Paracoccus dentrificans (PDB Accession Code 2MTA). The distance shown is between eN of the redox cofactor tryptophan tryptophylquinone of methylamine dehydrogenase and the eN of the His-95 ligand of amicyanin.

Govindaraj, S., Eisenstein, E., Jones, L. H., Sanders-Loehr, J., Chistoserdov, A. Y., Davidson, V. L., and Edwards, S. L. 1994, Aromatic amine dehydrogenase, a second tryptophan tryptophylquinone enzyme. J. Bacterial. 176 292292929. 

McIntire,W. S., Wemmer, D. E., Christoserdov, A. Y., and Lindstrom, M. E., 1991, A new cofactor in a prokaryotic enzyme Tryptophan tryptophylquinone as the redox prosthetic group in methylamine dehydrogenase, Science 252 817n824. 

Wamcke, K., Brooks, H. B., Lee, H.-L, McCracken, J. L., Davidson, V. L., and Babcock, G. T., 1995, Stmcture of the dithionite-generated tryptophan tryptophylquinone cofactor radical in methylamine dehydrogenase revealed by ENDOR and ESEEM spectroscopies, J. Am. Chem. Soc. 117 10063nl0075. 

We have been interested in the biological electron transfer between the cofactor tryptophan tryptophylquinone (TTQ) and a type I copper center." " The former is part of the membrane enzyme, methyl amine dehydrogenase (MADH), while the latter is the redox center of the blue copper protein. 

---