Chemical probes into the active centre of a heme thiolate monoxygenase

  • P K Bhattacharyya
  • T B Samanta
  • A H J Ullah
  • I C Gunsalus
Organic

Abstract

Linalool-8-monoxygenase, a typical bacterial P-450 heme thiolase, shows a high degree of substrate specificity towards linalool. The active site of the pure enzyme has been probed with a large number of substrate analogues with systematic alterations or conformational variations in the linalool molecule. The comparison of three parameters, the mo→mos conversion of the enzyme as a result of substrate binding monitored at 392 nm, theKD of the analogues giving information about energies of association and the relative turnover as substrate have given information about the space-filling characteristics of the substrates in the enzyme cleft, the number of contacts the molecules make with the respective domains of the enzyme and the distance of the site undergoing hydroxylation from the oxygen site, respectively. The data permit the conclusion that linalool makes contact with the enzyme by hydrogen bonding with the hydroxyl group as well through hydrophobic association with all the eight carbons carrying hydrogen in the molecules.

Keywords

Enzymes oxygenases P-450 hydroxylases structure of monooxygenase substrate analogues enzyme kinetics intermolecular associations 

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References

  1. Boatman S and Hauser 1967Org. Synth. (New York: John Wiley)47 87Google Scholar
  2. Gunsalus I C and Sligar S G 1978Adv. Enzymol. 47 1Google Scholar
  3. Ullah A H J, Bhattacharyya P K, Bhaktavatsalam J, Wagner G C and Gunsalus I C 1983Fed. Proc. 42 1897Google Scholar

Copyright information

© Indian Academy of Sciences 1984

Authors and Affiliations

  • P K Bhattacharyya
    • 1
    • 2
  • T B Samanta
    • 1
  • A H J Ullah
    • 1
  • I C Gunsalus
    • 1
  1. 1.Department of BiochemistryUniversity of IllinoisUrbanaUSA
  2. 2.Department of Organic ChemistryIndian Institute of ScienceBangaloreIndia

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