Tags

Type your tag names separated by a space and hit enter

Multiple forms of xylose reductase in Candida intermedia: comparison of their functional properties using quantitative structure-activity relationships, steady-state kinetic analysis, and pH studies.
J Agric Food Chem. 2003 Dec 31; 51(27):7930-5.JA

Abstract

The xylose-fermenting yeast Candida intermedia produces two isoforms of xylose reductase: one is NADPH-dependent (monospecific xylose reductase; msXR), and another is shown here to prefer NADH approximately 4-fold over NADPH (dual specific xylose reductase; dsXR). To compare the functional properties of the isozymes, a steady-state kinetic analysis for the reaction d-xylose + NAD(P)H + H(+) <--> xylitol + NAD(P)(+) was carried out and specificity constants (k(cat)/K(aldehyde)) were measured for the reduction of a series of aldehydes differing in side-chain size as well as hydrogen-bonding capabilities with the substrate binding pocket of the enzyme. dsXR binds NAD(P)(+) (K(iNAD+) = 70 microM; K(iNADP+) = 55 microM) weakly and NADH (K(i) = 8 microM) about as tightly as NADPH (K(i) = 14 microM). msXR shows uniform binding of NADPH and NADP(+) (K(iNADP+) approximately K(iNADPH) = 20 microM). A quantitative structure-activity relationship analysis was carried out by correlating logarithmic k(cat)/K(aldehyde) values for dsXR with corresponding logarithmic k(cat)/K(aldehyde) values for msXR. This correlation is linear with a slope of approximately 1 (r (2) = 0.912), indicating that no isozyme-related pattern of substrate specificity prevails and aldehyde-binding modes are identical in both XR forms. Binary complexes of dsXR-NADH and msXR-NADPH show the same macroscopic pK of approximately 9.0-9.5, above which the activity is lost in both enzymes. A lower pK of 7.4 is seen for dsXR-NADPH. Specificity for NADH and greater binding affinity for NAD(P)H than NAD(P)(+) are thus the main features of enzymic function that distinguish dsXR from msXR.

Authors+Show Affiliations

Institute of Biotechnology, Graz University of Technology, Petersgasse 12/I, A-8010 Graz, Austria. bernd.nidetzky@tugraz.atNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

14690376

Citation

Nidetzky, Bernd, et al. "Multiple Forms of Xylose Reductase in Candida Intermedia: Comparison of Their Functional Properties Using Quantitative Structure-activity Relationships, Steady-state Kinetic Analysis, and pH Studies." Journal of Agricultural and Food Chemistry, vol. 51, no. 27, 2003, pp. 7930-5.
Nidetzky B, Brüggler K, Kratzer R, et al. Multiple forms of xylose reductase in Candida intermedia: comparison of their functional properties using quantitative structure-activity relationships, steady-state kinetic analysis, and pH studies. J Agric Food Chem. 2003;51(27):7930-5.
Nidetzky, B., Brüggler, K., Kratzer, R., & Mayr, P. (2003). Multiple forms of xylose reductase in Candida intermedia: comparison of their functional properties using quantitative structure-activity relationships, steady-state kinetic analysis, and pH studies. Journal of Agricultural and Food Chemistry, 51(27), 7930-5.
Nidetzky B, et al. Multiple Forms of Xylose Reductase in Candida Intermedia: Comparison of Their Functional Properties Using Quantitative Structure-activity Relationships, Steady-state Kinetic Analysis, and pH Studies. J Agric Food Chem. 2003 Dec 31;51(27):7930-5. PubMed PMID: 14690376.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Multiple forms of xylose reductase in Candida intermedia: comparison of their functional properties using quantitative structure-activity relationships, steady-state kinetic analysis, and pH studies. AU - Nidetzky,Bernd, AU - Brüggler,Kaspar, AU - Kratzer,Regina, AU - Mayr,Peter, PY - 2003/12/24/pubmed PY - 2004/3/6/medline PY - 2003/12/24/entrez SP - 7930 EP - 5 JF - Journal of agricultural and food chemistry JO - J. Agric. Food Chem. VL - 51 IS - 27 N2 - The xylose-fermenting yeast Candida intermedia produces two isoforms of xylose reductase: one is NADPH-dependent (monospecific xylose reductase; msXR), and another is shown here to prefer NADH approximately 4-fold over NADPH (dual specific xylose reductase; dsXR). To compare the functional properties of the isozymes, a steady-state kinetic analysis for the reaction d-xylose + NAD(P)H + H(+) <--> xylitol + NAD(P)(+) was carried out and specificity constants (k(cat)/K(aldehyde)) were measured for the reduction of a series of aldehydes differing in side-chain size as well as hydrogen-bonding capabilities with the substrate binding pocket of the enzyme. dsXR binds NAD(P)(+) (K(iNAD+) = 70 microM; K(iNADP+) = 55 microM) weakly and NADH (K(i) = 8 microM) about as tightly as NADPH (K(i) = 14 microM). msXR shows uniform binding of NADPH and NADP(+) (K(iNADP+) approximately K(iNADPH) = 20 microM). A quantitative structure-activity relationship analysis was carried out by correlating logarithmic k(cat)/K(aldehyde) values for dsXR with corresponding logarithmic k(cat)/K(aldehyde) values for msXR. This correlation is linear with a slope of approximately 1 (r (2) = 0.912), indicating that no isozyme-related pattern of substrate specificity prevails and aldehyde-binding modes are identical in both XR forms. Binary complexes of dsXR-NADH and msXR-NADPH show the same macroscopic pK of approximately 9.0-9.5, above which the activity is lost in both enzymes. A lower pK of 7.4 is seen for dsXR-NADPH. Specificity for NADH and greater binding affinity for NAD(P)H than NAD(P)(+) are thus the main features of enzymic function that distinguish dsXR from msXR. SN - 0021-8561 UR - https://www.unboundmedicine.com/medline/citation/14690376/Multiple_forms_of_xylose_reductase_in_Candida_intermedia:_comparison_of_their_functional_properties_using_quantitative_structure_activity_relationships_steady_state_kinetic_analysis_and_pH_studies_ L2 - https://dx.doi.org/10.1021/jf034426j DB - PRIME DP - Unbound Medicine ER -