EC 3.2.1.149     
Accepted name: β-primeverosidase
Reaction: a 6-O-(β-D-xylopyranosyl)-β-D-glucopyranoside + H2O = 6-O-(β-D-xylopyranosyl)-β-D-glucopyranose + an alcohol
Glossary: primeverose = 6-O-(β-D-xylopyranosyl)-D-glucose
vicianose = 6-O-(α-L-arabinopyranosyl)-D-glucose
Systematic name: 6-O-(β-D-xylopyranosyl)-β-D-glucopyranoside 6-O-(β-D-xylosyl)-β-D-glucohydrolase
Comments: The enzyme is responsible for the formation of the alcoholic aroma in oolong and black tea. In addition to β-primeverosides [i.e. 6-O-(β-D-xylopyranosyl)-β-D-glucopyranosides], it also hydrolyses 6-O-(β-D-apiofuranosyl)-β-D-glucopyranosides and, less rapidly, β-vicianosides and 6-O-(α-L-arabinofuranosyl)-β-D-glucopyranosides, but not β-glucosides. Geranyl-, linaloyl-, benzyl- and p-nitrophenol glycosides are all hydrolysed.
References:
1.  Ijima, Y., Ogawa, K., Watanabe, N., Usui, T., Ohnishi-Kameyama, M., Nagata, T. and Sakata, K. Characterization of β-primeverosidase, being concerned with alcoholic aroma formation in tea leaves to be processed into black tea, and preliminary observations on its substrate specificity. J. Agric. Food Chem. 46 (1998) 1712–1718.
2.  Ogawa, K., Ijima, Y., Guo, W., Watanabe, N., Usui, T., Dong, S., Tong, Q. and Sakata, K. Purification of a β-primeverosidase concerned with alcoholic aroma formation in tea leaves (cv. Shuxian) to be processed to oolong tea. J. Agric. Food Chem. 45 (1997) 877–882.
[EC 3.2.1.149 created 2001]