Isolation and Characterization of XantIsolation and Characterization of Xanthine Oxidase from Tissues of Benign and Malignant Colon Tumors Patients

The present research included the determination of xanthine oxidase XO in tissues of benign and malignant colon tumor patients.
Six samples were collected from patients in surgery unit in Al-Zahrawi hospital in Nineveh Governorate, three of them were benign and the others were malignant colon tumors.
The results showed that there are (62%) increase in the specific activity of the enzyme in malignant than benign.
The research also included an isolation and partial purification of XO using gel filtration chromatography from benign and malignant colon tumor tissues. The number of purification folds was (12) fold from benign and (17) folds from malignant.
The molecular weight of XO was determined using gel filtration on sephadex G-100 and it was found to be (199000 2000 , 191000 2000) dalton from benign and malignant colon tumor respectively.
The results also showed that the enzyme gave a maximum activity at (1.510-4 M) of xanthine as a substrate and phosphate buffer at pH (8.5), temperature of (40/C) and incubation time (6 minutes). Using linweaver-Burk plot, the Km was (2.5 10-4M) and Vmax was ( 7.1 10-5) U/ml.
The research also shows an inhibition effect of some metal ions like Cu+2, Hg+2, Ag+2 (but not by Co+2) and some chemical compounds like N-acetyl cysteine,
1-phenl-3-pyrazolidinone on XO activity.