Citation
Mariappan, Vanitha
(2005)
Partial Purification and Characterisation of Alkaline Phosphatase from Hepatopancreas and Intertine of Red Tilapia, (Tilapia Mossambica).
Masters thesis, Universiti Putra Malaysia.
Abstract
Alkaline phosphatase (EC 3.1.3.1) is a metalloenzyme, which catalyze
nonspecific hydrolysis of phosphate monoesters. Partial purification
was conducted on alkaline phosphatase (ALP) extracted from
hepatopancreas and intestine of red tilapia, (Tilapia mossombica) using
two main steps - ammonium sulphate precipitation and ion exchange
chromatography on DEAE - 52. Samples from the ion-exchange step
were analysed for ALP activities and characterised by SDS-PAGE.
SDS-PAGE analysis showed 2 identical bands and was found to have
molecular weight of 68,000 Da (hepatopancreas ALP) and 180,500 Da
(intestinal ALP) subunits. Overall, purification fold obtained from the
final step are 1.8 and 21.9 for hepatopancreas and intestinal
respectively, with recovery of only 0.22% from hepatopancreas and
0.01% from intestine. The specific activity of the enzyme was 1.72 X 10-
2 pmol min-1 mg-1 and 2.93 X 10-1 pmol min-1 mg-1 from hepatopancreas
and intestine respectively. The ALP from hepatopancreas remained
stable at temperatures up to 50°C, and ALP from intestine enzyme had
an optimum temperature of 60°C. The optimum pH for both
hepatopancreas and intestine ALP of Tilapia mossambica is pH 10. The
positive monovalent alkali metal ions (Li+, Na+ and K+) have no effect
on the ALP enzyme activity. However, the positive divalent alkali
metal ions (Mg2+a nd Ca2+)a ctivate the enzyme activities. Heavy metal
ions (Zn2+, CU~+C,d 2+a nd Hg2+) were found to inhibit the enzyme
activity.
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