Abstract
An alcohol dehydrogenase (ADH) was extracted from grape berries with dithiothreitol and glycerol present in the extraction medium. The enzyme was purified 297-fold with 81% yield by DEAE cellulose and affinity chromatographies (Blue Sepharose CL-6B). The enzyme so obtained, homogeneous in polyacrylamide gel electrophoresis, can be stored at least one year at -20°C. The optimum pH for grape ADH was found to be 9.2 to 9.3 for ethanol oxidation and 5.8 to 5.9 for acetaldehyde reduction. The iso-electric point was 5.5 ± 0.2. The molecular weight values determined by gel filtration, polyacrylamide gradient gel electrophoresis, and SDS polyacrylamide gel electrophoresis are indicative of a dimeric structure for this enzyme which is probably constituted by two identical subunits of MW = 45 000 ± 2000. Inhibition studies show that grape ADH is a metallo enzyme with SH groups essential for enzyme activity. The results obtained using ethanol as the inhibitor indicate that during carbonic maceration, the limitation of percent alcohol observed is not related to the inhibitor effect of the ethanol on grape ADH.
- Received March 1985.
- Copyright 1986 by the American Society for Enology and Viticulture
Sign in for ASEV members
ASEV Members, please sign in at ASEV to access the journal online.
Sign in for Institutional and Non-member Subscribers
Log in using your username and password
Pay Per Article - You may access this article (from the computer you are currently using) for 2 day for US$10.00
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.