A Preliminary study of the invertase activity in coconut
No Thumbnail Available
Date
1977
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Sri Lanka (Colombo Campus): UC(MED).
Abstract
AB : A ` particulate ` invertase preparation of low activity (sedimenting in the 900 g fraction) was extracted from the stalk and mesocarp tissues of coconut (Cocos nucifera L.). The activity o invertase was found to increase linearly with the time of incubation (0 - 3h). Initial velocity was directly proportional to enzyme concentration, only in the low concentration ranges. The initial velocity decreased at enzyme concentrations higher than 0.13 mg protein per 2.0 ml of incubation mixture. Treatment of the particulate enzyme with 0.1 present and 0.5 present (v/v) of the nonionic surface active agent, Triton X - 100, solubilized 71 percent and 76 percent of the invertase. Incorporation of the non-acidic thiol, mercaptoethanol into the reaction mixture, caused significant activation of the invertase. This suggested the possibility of an SH group participating in the catalytic activity of the enzyme. In addition, mercaptoethanol may cause enzyme reactivation by reducing the quinones formed by the oxidation of polyphenols. Consequently, the low activity observed in the absence of mercaptoethanol was probally due in part, to an inactivation of the enzyme by quinones. The enzyme was found to be inactivated by the metal chelating agent, ethylene diamine tetracetate (EDTA) at 5 X 10-3 and 5 X 10-4 M concentrations. This finding suggested that invertase is probably a metalloenzyme. It was also found that the inactivation of the enzyme by EDTA (10-2 M) was not reversed by mercaptoethanol. This may indicate that the removal of the metal in question by EDTA, causes an irreversible denaturation of the enzyme. Polyphenols found in the enzyme preparation were found to interfere with the reduction of the dinitrosalicylic acid reagent. The use of insoluble polyclar in the extracting medium to remove these interfering substances, is suggested.
Description
Dissertation: M.Sc., University of Sri Lanka (Colombo Campus): UC(MED), 1977.
Keywords
Beta-fructofuranosidase
Citation
ALLES, NH, A Preliminary study of the invertase activity in coconut, University of Sri Lanka (Colombo Campus) UC(MED), 1977: 47p.