FEBS Letters
Volume 580, Issue 1 , Pages 67-71, 9 January 2006

Differences in catalytic activity between rat testicular and ovarian carbonyl reductases are due to two amino acids

Edited by Miguel De la Rosa

  • Michel A. Sciotti

      Affiliations

    • Institute of Clinical Chemistry, 3010 Bern, Switzerland
    • ,
  • Steven Tam

      Affiliations

    • Department of Medicine, 0693 University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0693, USA
    • ,
  • Bendicht Wermuth

      Affiliations

    • Institute of Clinical Chemistry, 3010 Bern, Switzerland
    • Corresponding Author InformationCorresponding authors. Fax: +41 31 632 4862 (B. Wermuth), +1 619 543 7069 (M.E. Baker).
    • ,
  • Michael E. Baker

      Affiliations

    • Department of Medicine, 0693 University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0693, USA
    • Corresponding Author InformationCorresponding authors. Fax: +41 31 632 4862 (B. Wermuth), +1 619 543 7069 (M.E. Baker).

Received 7 September 2005; received in revised form 26 October 2005; accepted 15 November 2005. published online 05 December 2005.

Abstract 

The sequences of rat testis carbonyl reductase (rCR1) and rat ovary carbonyl reductase (rCR2) are 98% identical, differing only at amino acids 140, 141, 143, 235 and 238. Despite such strong sequence identity, we find that rCR1 and rCR2 have different catalytic constants for metabolism of menadione and 4-benzoyl-pyridine. Compared to rCR1, rCR2 has a 20-fold lower Km and 5-fold lower kcat towards menadione and a 7-fold lower Km and 7-fold lower kcat towards 4-benzoyl-pyridine. We constructed hybrids of rCR1 and rCR2 that were changed at either residues 140, 141 and 143 or residues 235 and 238. rCR1 with residues 140, 141 and 143 of rCR2 has similar catalytic efficiency for menadione and 4-benzoyl-pyridine as rCR1. rCR1 with Thr-235 and Glu-238 of rCR2 has the catalytic constants of rCR2, indicating that it is this part of rCR2 that contributes to its lower Km for menadione and 4-benzoyl-pyridine. Comparisons of three-dimensional models of rCR1 and rCR2 show how Thr-235 and Glu-238 stabilize rCR2 binding of NADPH and menadione.

Keywords: Carbonyl reductase, Enzyme evolution, Xenobiotics

To access this article, please choose from the options below

Login to an existing account or Register a new account.

  • Purchase this article for 31.50 USD (You must login/register to purchase this article)

    Online access for 24 hours. The PDF version can be downloaded as your permanent record.

  • Subscribe to this title

    Get unlimited online access to this article and all other articles in this title 24/7 for one year.

  • Claim access now

    For current subscribers with Society Membership or Account Number.

  • Visit SciVerse ScienceDirect to see if you have access via your institution.
 

PII: S0014-5793(05)01419-5

doi:10.1016/j.febslet.2005.11.049

FEBS Letters
Volume 580, Issue 1 , Pages 67-71, 9 January 2006

Article Tools

* Image Usage & Resolution