Superoxide dismutase from Hevea brasiliensis leaves
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Komgrit Sincharoenrung, D. of Biochemistry, F.of Sci., PSU.
Wallie Suvachittanont, Assoc. Prof., D. of Biochemistry, F.of Sci., PSU.
Corresponding e-mail : komgrits@yahoo.com
Grant : Graduate Budget
Presented : The 3rd Regional IMT-GT UNINET Conference IMT-GT 2000,
10-12 October 2000, Medan, Indonesia
: The 26th Congress on Science and Technology of Thailand, 18-20 October 2000, Bangkok, Thailand
Key words : superoxide dismutase, Hevea brasiliensis, rubber tree
Superoxide dismutase (SOD) catalyses the dismutation reaction of O2- +O2-+ ® H2O2+O2 to reduce the reactive oxygen which is harmful for all creatures. When rubber tree leaf, clone RRIM 600, was extracted SOD activity was found to be 1,588±418 Unit/g using NBT method (Beyer and Fri-dovich, 1987). SOD activity from mature and from medium leaf extract showed higher SOD activity
than the very young leaf extract (1,498±448 U/g, 1,527±501 U/g and 1,130±529 U/g, respectively). SOD activity was also found in petiole but with lesser than extent. SOD in leaf extract is stable and
can be kept at -20oC and -70oC for 3 months. The stability was lesser at 4oC and -10oC. KCN, NaCN, b-mercaptoethanol, H2O2 and SDS inhibit the activity of SOD. When the leaf extract was boiled at
100oC for 3 hours, 55% of the SOD activity remained. However when the boiled enzyme was sub-
jected to polyacrylamide gel electrophoresis, no SOD activity was detected by activity staining. It
was possible that other substances in leaf extract gave similar result as SOD.
It has been shown that there is a relation between SOD activity and dried bark disease. This
could afftect the rubber latex yield. Some correlation between SOD in leaf extract and total Dried Rubber Content (DRC) in rubber latex was found, which correlation coefficient of 0.545. Attempts have been made to purify SOD from leaf extract by 40-70% ammoniumsulphate precipitation. It
was found that most of the activity remained in the supernatant.
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