Investigations of the Enzyme Mechanism

The same holds true if the detailed enzymatic steps were known. However, as no complex of its natural substrates, scytalone or vermelone, is available the proposed mechanism of SD, the catalysis of a syn l -elimination of water from scytalone and subsequent aromatization [Lundquist et al., 1994], remains to be proven experimentally. 

Though much smaller and much less lipophilic, both scytalone and vermelone share some structural features with the co-crystallized competitive inhibitors. To 

ATVTYRXING BMKFAGIB9H IRHTSFOOBG IP- 6PPSKB BNSVAADIlOV mBMOSSEVB nth.t.klfa vwKfAg..p.e.f. 

Although the last step in the reaction sequence, abstraction of a proton from C4, followed by aromatization of the a, 6-unsaturated ketone, will occur spontaneously without assistance by a protein, it seems reasonable to assume that product formation is accelerated considerably by an enzymatic mechanism. Again, DFT calculations suggest that deprotonated HisllO could accept a proton from the previously generated water molecule, which in turn accepts the C4 proton. Protonation of the ketone could occur by the catalytic water bound by the two tyrosines. 

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Sandeep Kumar received his M.S. in chemistry from the Indian Institute of Technology, Kanpur, India, in 2003. He received his Ph.D. from OSU in 2008, where he worked on the catalytic mechanism of DNA polymerases under the supervision of Professor Ming-Daw Tsai. He is currently a post-doctoral researcher with Professors Karin Musier-Forsyth and Christopher Hadad at OSU. His areas of interest include molecular modeling and quantum mechanical investigations of the enzyme mechanisms. 

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