TY - JOUR
T1 - Characterization of rabbit aldose reductase-like protein with 3β-hydroxysteroid dehydrogenase activity
AU - Endo, Satoshi
AU - Matsunaga, Toshiyuki
AU - Kumada, Sho
AU - Fujimoto, Airi
AU - Ohno, Satoshi
AU - El-Kabbani, Ossama
AU - Hu, Dawei
AU - Toyooka, Naoki
AU - Mano, Jun'Ichi
AU - Tajima, Kazuo
AU - Hara, Akira
N1 - Funding Information:
This work was partly founded by Grant-in-aid for Young Scientists (B) and Scientific Research (C) from the Japan Society for the Promotion of Science , and by a Sasakawa Scientific Research Grant from Japan Science Society .
PY - 2012/11/1
Y1 - 2012/11/1
N2 - In this study, we isolated the cDNA for a rabbit aldose reductase-like protein that shared an 86% sequence identity to human aldo-keto reductase (AKR)1 1B10 and has been assigned as AKR1B19 in the AKR superfamily. The purified recombinant AKR1B19 was similar to AKR1B10 and rabbit aldose reductase (AKR1B2) in the substrate specificity for various aldehydes and α-dicarbonyl compounds. In contrast to AKR1B10 and AKR1B2, AKR1B19 efficiently reduced 3-keto-5α/β-dihydro-C19/C21/C24-steroids into the corresponding 3β-hydroxysteroids, showing Km of 1.3-9.1 μM and kcat of 1.1-7.6 min-1. The stereospecific reduction was also observed in the metabolism of 5α- and 5β- dihydrotestosterones in AKR1B19-overexpressing cells. The mRNA for AKR1B19 was ubiquitously expressed in rabbit tissues, and the enzyme was co-purified with 3β-hydroxysteroid dehydrogenase activity from the lung. Thus, AKR1B19 may function as a 3-ketoreductase, as well as a defense system against cytotoxic carbonyl compounds in rabbit tissues. The molecular determinants for the unique 3-ketoreductase activity were investigated by replacement of Phe303 and Met304 in AKR1B19 with Gln and Ser, respectively, in AKR1B10. Single and double mutations (F303Q, M304S and F303Q/M304S) significantly impaired this activity, suggesting the two residues play critical roles in recognition of the steroidal substrate.
AB - In this study, we isolated the cDNA for a rabbit aldose reductase-like protein that shared an 86% sequence identity to human aldo-keto reductase (AKR)1 1B10 and has been assigned as AKR1B19 in the AKR superfamily. The purified recombinant AKR1B19 was similar to AKR1B10 and rabbit aldose reductase (AKR1B2) in the substrate specificity for various aldehydes and α-dicarbonyl compounds. In contrast to AKR1B10 and AKR1B2, AKR1B19 efficiently reduced 3-keto-5α/β-dihydro-C19/C21/C24-steroids into the corresponding 3β-hydroxysteroids, showing Km of 1.3-9.1 μM and kcat of 1.1-7.6 min-1. The stereospecific reduction was also observed in the metabolism of 5α- and 5β- dihydrotestosterones in AKR1B19-overexpressing cells. The mRNA for AKR1B19 was ubiquitously expressed in rabbit tissues, and the enzyme was co-purified with 3β-hydroxysteroid dehydrogenase activity from the lung. Thus, AKR1B19 may function as a 3-ketoreductase, as well as a defense system against cytotoxic carbonyl compounds in rabbit tissues. The molecular determinants for the unique 3-ketoreductase activity were investigated by replacement of Phe303 and Met304 in AKR1B19 with Gln and Ser, respectively, in AKR1B10. Single and double mutations (F303Q, M304S and F303Q/M304S) significantly impaired this activity, suggesting the two residues play critical roles in recognition of the steroidal substrate.
KW - 3β-Hydroxysteroid dehydrogenase
KW - 4-Oxo-2-nonenal
KW - AKR1B10
KW - Aldo-keto reductase
KW - Aldose reductase
UR - http://www.scopus.com/inward/record.url?scp=84865470535&partnerID=8YFLogxK
U2 - 10.1016/j.abb.2012.07.012
DO - 10.1016/j.abb.2012.07.012
M3 - 学術論文
C2 - 22874434
AN - SCOPUS:84865470535
SN - 0003-9861
VL - 527
SP - 23
EP - 30
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 1
ER -