4-Hydroxy-7-methoxy-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl glucoside beta-D-glucosidase explained

4-Hydroxy-7-methoxy-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl glucoside beta-D-glucosidase
Ec Number:	3.2.1.182

4-Hydroxy-7-methoxy-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl glucoside beta-D-glucosidase (DIMBOAGlc hydrolase, DIMBOA glucosidase) is an enzyme with systematic name (2R)-4-hydroxy-7-methoxy-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl beta-D-glucopyranoside beta-D-glucosidase.^{[1] [2] [3] [4] [5] [6]} This enzyme catalyses the following chemical reaction

(1) (2R)-4-hydroxy-7-methoxy-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl beta-D-glucopyranoside + H₂O

\rightleftharpoons 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one + D-glucose

(2) (2R)-4-hydroxy-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl beta-D-glucopyranoside + H₂O

\rightleftharpoons 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one + D-glucose

The enzyme from Triticum aestivum (wheat) has a higher affinity for DIMBOA glucoside than DIBOA glucoside.

Notes and References

1. Sue M, Ishihara A, Iwamura H . Purification and characterization of a hydroxamic acid glucoside beta-glucosidase from wheat (Triticum aestivum L.) seedlings . Planta . 210 . 3 . 432–8 . February 2000 . 10750901 . 10.1007/s004250050029 . 6266316 .
2. Sue M, Ishihara A, Iwamura H . Purification and characterization of a beta-glucosidase from rye (Secale cereale L.) seedlings . Plant Science . 155 . 1 . 67–74 . June 2000 . 10773341 . 10.1016/s0168-9452(00)00204-1 .
3. Czjzek M, Cicek M, Zamboni V, Bevan DR, Henrissat B, Esen A . The mechanism of substrate (aglycone) specificity in beta -glucosidases is revealed by crystal structures of mutant maize beta -glucosidase-DIMBOA, -DIMBOAGlc, and -dhurrin complexes . Proceedings of the National Academy of Sciences of the United States of America . 97 . 25 . 13555–60 . December 2000 . 11106394 . 17614 . 10.1073/pnas.97.25.13555 . 2000PNAS...9713555C . free .
4. Cloning of a plastidic rye (Secale cereale) β-glucosidase cDNA and its expression in Escherichia coli . Nikus J, Esen A, Jonsson LM . Physiol. Plant. . 2003 . 118 . 3 . 337–348 . 10.1034/j.1399-3054.2003.00118.x.
5. Sue M, Yamazaki K, Yajima S, Nomura T, Matsukawa T, Iwamura H, Miyamoto T . Molecular and structural characterization of hexameric beta-D-glucosidases in wheat and rye . Plant Physiology . 141 . 4 . 1237–47 . August 2006 . 16751439 . 1533919 . 10.1104/pp.106.077693 .
6. Sue M, Nakamura C, Miyamoto T, Yajima S . Active-site architecture of benzoxazinone-glucoside β-D-glucosidases in Triticeae . Plant Science . 180 . 2 . 268–75 . February 2011 . 21421370 . 10.1016/j.plantsci.2010.09.001 .