Abstract:
A general survey on lipase activity in plant seeds showed that seeds of Cucumis melo `form garma cimitain significant lipolytic activity. Enzymic characteristics of this seed lipase were therefore studied The lipase was found to AV.exhibit two pH optima, i.e. 4.0 and 6.0 in both the resting and germinated seeds. Lipase activity, however, increased considerably on germination. From 3.4 units/g at pH 6.0 in the resting stage, the activity increased to 11.1 units/g after germination to a primary root length of 3 cm. Lipases having pH optima 4.0 and 6.0 showed different stabilities at pH 6.0 and 40°C which further suggest the presence of two different lipases in the seeds of Cucumis melo. Optimum temperature for the enzyme activity under the assay conditions was found to be 40°C and the enzyme was rapidly inactivated at temperatures above 40°C. The enzyme was activiated by low concentrations of calcium and sodium ions. The lipase hydrolysed ricinoleic acid glycerides of castor oil faster than the glycerides of mustard oil or soyabean oil. The order of activity in the organic solvent system was found to be Ethyl methylketone H di-isopropyl other H n-hrpiane H-cyclohexanol. = cyclohexane. Further work in order to isolate` and characterise the lipases as indicated above is in progress.
Page(s):
6-11
DOI:
DOI not available
Published:
Journal: Pakistan Journal of Biochemistry, Volume: 11, Issue: 1--2, Year: 1978