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Substrate Specificity, Inhibitor Selectivity and Structure-Function Relationships of Aldo-Keto Reductase 1B15: A Novel Human Retinaldehyde Reductase.

Giménez-Dejoz J, Kolář MH, Ruiz FX, Crespo I, Cousido-Siah A, Podjarny A, Barski OA, Fanfrlík J, Parés X, Farrés J, Porté S - PLoS ONE (2015)

Bottom Line: In contrast to AKR1B10, which strongly prefers all-trans-retinaldehyde, AKR1B15 exhibits superior catalytic efficiency with 9-cis-retinaldehyde, the best substrate found for this enzyme.Several typical AKR inhibitors do not significantly affect AKR1B15 activity.Amino acid substitutions clustered in loops A and C result in a smaller, more hydrophobic and more rigid active site in AKR1B15 compared with the AKR1B10 pocket, consistent with distinct substrate specificity and narrower inhibitor selectivity for AKR1B15.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain.

ABSTRACT
Human aldo-keto reductase 1B15 (AKR1B15) is a newly discovered enzyme which shares 92% amino acid sequence identity with AKR1B10. While AKR1B10 is a well characterized enzyme with high retinaldehyde reductase activity, involved in the development of several cancer types, the enzymatic activity and physiological role of AKR1B15 are still poorly known. Here, the purified recombinant enzyme has been subjected to substrate specificity characterization, kinetic analysis and inhibitor screening, combined with structural modeling. AKR1B15 is active towards a variety of carbonyl substrates, including retinoids, with lower kcat and Km values than AKR1B10. In contrast to AKR1B10, which strongly prefers all-trans-retinaldehyde, AKR1B15 exhibits superior catalytic efficiency with 9-cis-retinaldehyde, the best substrate found for this enzyme. With ketone and dicarbonyl substrates, AKR1B15 also shows higher catalytic activity than AKR1B10. Several typical AKR inhibitors do not significantly affect AKR1B15 activity. Amino acid substitutions clustered in loops A and C result in a smaller, more hydrophobic and more rigid active site in AKR1B15 compared with the AKR1B10 pocket, consistent with distinct substrate specificity and narrower inhibitor selectivity for AKR1B15.

No MeSH data available.


Related in: MedlinePlus

Molecular structure of compound JF0064, 2,2’,3,3’,5,5’,6,6’-octafluoro-4,4’-biphenyldiol.
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pone.0134506.g003: Molecular structure of compound JF0064, 2,2’,3,3’,5,5’,6,6’-octafluoro-4,4’-biphenyldiol.

Mentions: Seven AKR inhibitors were tested against AKR1B15 using D,L-glyceraldehyde as substrate (Table 3). Among these inhibitors, there are five of the carboxylic acid type (tolrestat, epalrestat, oleanolic acid, sulindac and lithocholic acid), one of cyclic imide type (sorbinil) and one non-classical aldose reductase inhibitor or ARI (JF0064, which has been recently described by Cousido-Siah et al [15], Fig 3). Tolrestat, JF0064 and sulindac are potent inhibitors of AKR1B1 as well as of AKR1B10 (with IC50<10 μM for both enzymes). Sorbinil and epalrestat are more selective against AKR1B1 [50,51], while oleanolic and lithocholic acid are more selective against AKR1B10 [52]. For AKR1B15, only JF0064 showed a significant inhibition (IC50 = 0.034 ± 0.005 μM, Table 3), much stronger than for AKR1B1 and AKR1B10 [15]. The steroid lithocholic acid was found to be an inhibitor of AKR1B15, in agreement with the reported observation that certain steroids are good substrates for this enzyme [16].


Substrate Specificity, Inhibitor Selectivity and Structure-Function Relationships of Aldo-Keto Reductase 1B15: A Novel Human Retinaldehyde Reductase.

Giménez-Dejoz J, Kolář MH, Ruiz FX, Crespo I, Cousido-Siah A, Podjarny A, Barski OA, Fanfrlík J, Parés X, Farrés J, Porté S - PLoS ONE (2015)

Molecular structure of compound JF0064, 2,2’,3,3’,5,5’,6,6’-octafluoro-4,4’-biphenyldiol.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4519324&req=5

pone.0134506.g003: Molecular structure of compound JF0064, 2,2’,3,3’,5,5’,6,6’-octafluoro-4,4’-biphenyldiol.
Mentions: Seven AKR inhibitors were tested against AKR1B15 using D,L-glyceraldehyde as substrate (Table 3). Among these inhibitors, there are five of the carboxylic acid type (tolrestat, epalrestat, oleanolic acid, sulindac and lithocholic acid), one of cyclic imide type (sorbinil) and one non-classical aldose reductase inhibitor or ARI (JF0064, which has been recently described by Cousido-Siah et al [15], Fig 3). Tolrestat, JF0064 and sulindac are potent inhibitors of AKR1B1 as well as of AKR1B10 (with IC50<10 μM for both enzymes). Sorbinil and epalrestat are more selective against AKR1B1 [50,51], while oleanolic and lithocholic acid are more selective against AKR1B10 [52]. For AKR1B15, only JF0064 showed a significant inhibition (IC50 = 0.034 ± 0.005 μM, Table 3), much stronger than for AKR1B1 and AKR1B10 [15]. The steroid lithocholic acid was found to be an inhibitor of AKR1B15, in agreement with the reported observation that certain steroids are good substrates for this enzyme [16].

Bottom Line: In contrast to AKR1B10, which strongly prefers all-trans-retinaldehyde, AKR1B15 exhibits superior catalytic efficiency with 9-cis-retinaldehyde, the best substrate found for this enzyme.Several typical AKR inhibitors do not significantly affect AKR1B15 activity.Amino acid substitutions clustered in loops A and C result in a smaller, more hydrophobic and more rigid active site in AKR1B15 compared with the AKR1B10 pocket, consistent with distinct substrate specificity and narrower inhibitor selectivity for AKR1B15.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain.

ABSTRACT
Human aldo-keto reductase 1B15 (AKR1B15) is a newly discovered enzyme which shares 92% amino acid sequence identity with AKR1B10. While AKR1B10 is a well characterized enzyme with high retinaldehyde reductase activity, involved in the development of several cancer types, the enzymatic activity and physiological role of AKR1B15 are still poorly known. Here, the purified recombinant enzyme has been subjected to substrate specificity characterization, kinetic analysis and inhibitor screening, combined with structural modeling. AKR1B15 is active towards a variety of carbonyl substrates, including retinoids, with lower kcat and Km values than AKR1B10. In contrast to AKR1B10, which strongly prefers all-trans-retinaldehyde, AKR1B15 exhibits superior catalytic efficiency with 9-cis-retinaldehyde, the best substrate found for this enzyme. With ketone and dicarbonyl substrates, AKR1B15 also shows higher catalytic activity than AKR1B10. Several typical AKR inhibitors do not significantly affect AKR1B15 activity. Amino acid substitutions clustered in loops A and C result in a smaller, more hydrophobic and more rigid active site in AKR1B15 compared with the AKR1B10 pocket, consistent with distinct substrate specificity and narrower inhibitor selectivity for AKR1B15.

No MeSH data available.


Related in: MedlinePlus