Mandić Ljuba M, Aćimović Jelena M, Jovanović Vesna B
Faculty of Chemistry, University of Belgrade, P.O. Box 158, Studentski trg 16, 11001 Belgrade, Serbia and Montenegro.
Clin Biochem. 2005 Apr;38(4):384-9. doi: 10.1016/j.clinbiochem.2005.01.002.
To have a reliable diagnostic test, the influence of urine pH on the determination of the total activity of N-acetyl-beta-D-glucosaminidase (NAG) and NAG isoenzyme activities was studied.
After ultrafiltration and dialysis of the acidic and alkaline urines, the B, A, and A2 forms of NAG were separated by ion-exchange chromatography on DEAE cellulose.
A significant decrease in the total activity of NAG in alkaline urines (pH around 8 or higher) was found, which makes this determination unreliable. Analysis of the isoenzymic profiles obtained for weakly acidic and alkaline urines (in the pH range from 5.5. to 10.0) showed that the percent fractions of the individual isoenzyme activities in the total NAG activity and their ratios changed only at pH values above 9.5.
The determination of the denoted isoenzymes of urinary NAG after ultrafiltration, dialysis, and chromatographic separation on DEAE cellulose is reliable in a wide range of alkaline pH values of urine.
为获得可靠的诊断试验，研究了尿液pH值对N - 乙酰 - β - D - 氨基葡萄糖苷酶（NAG）总活性及NAG同工酶活性测定的影响。
对酸性和碱性尿液进行超滤和透析后，通过在DEAE纤维素上进行离子交换色谱法分离NAG的B、A和A2形式。
发现碱性尿液（pH约为8或更高）中NAG的总活性显著降低，这使得该测定不可靠。对弱酸性和碱性尿液（pH范围为5.5至10.0）获得的同工酶谱分析表明，总NAG活性中各个同工酶活性的百分比分数及其比率仅在pH值高于9.5时发生变化。
在尿液的广泛碱性pH值范围内，经超滤、透析并在DEAE纤维素上进行色谱分离后测定尿NAG的指定同工酶是可靠的。
