Uricase Isolated from Seeds of Leek (Allium ampeloprasum), Celery (Apium graveolens) and Arugula (Eruca sativa)

الملخص

This research included isolation of uricase from the seeds of leek (Allium
ampeloprasum ), celery(Apium graveolens) and arugula(Eruca sativa). Studied the
factors effecting its activity and determination of its molecular weight. One proteinous
peak had been isolated by gel filtration (using sephadex (G-100)) from the proteinous
supernatant obtained using ammonium sulfate saturation(70%). The apparent
molecular weight of the isolated enzymes using gel filtration chromatography were
(59600+ 209) Dalton for leek, (59430+ 221) Dalton for celery and (59800+ 190)
Dalton for arugula .
The results also showed that the optimum conditions for the activity of uricase
isolated from seeds of leek, celery and arugula obtained at (100 μg/ml) of enzymes
concentration using (100, 100 and 120 mmol/l) of uric acid as a substrate, with borate
buffer solution at pH (7.0, 7.0, 6.5 ) for (15) minutes at (40, 40 and 35 C)
respectively. Using Line Weaver–Burk plot, the values of maximum velocity (Vmax)
and Michaelis constant (Km) were from to be (33.3 μmol/ min) and (83.3 mmol/l) for
leek, (40 μmol/ min) and (285.7 mmol/l) for celery while (27 μmol/ min) and (166.6
mmol/l) respectively for arugula.
When using 100 mM chemical compounds for mercuric chloride(HgCl2),
ferrous chloride (FeCl2) and ethylene diamine tetra acetic acid (EDTA) showed
decreased the activity of the enzyme, but calcium chloride (CaCl2), manganese
sulphate (MnSO4), magnesium sulphate (MgSO4) and potassium chloride (KCl)
increased the activity .