12270772 |
Cavallone D, Malagolini N, Frasca GM, Stefoni S, Serafini-Cessi F: Salt-precipitation method does not isolate to homogeneity Tamm-Horsfall glycoprotein from urine of proteinuric patients and pregnant women. Clin Biochem. 2002 Jul;35(5):405-10. OBJECTIVE: Assessment of the degree of purification of Tamm-Horsfall glycoprotein from anomalous urine. DESIGN AND METHODS: Two methods have been compared: the method of Tamm & Horsfall (T&H; method) consisting in the precipitation of THP by the addition to urine of NaCl up to 0.58 mol/L and the filtration of urine through a diatomaceous earth filter (DEF method) in which THP is selectively trapped because of its gelation/aggregation tendency. The purity of THP preparations has been evaluated by SDS-PAGE analysis and Western blotting developed with anti immunoglobulin G (IgG) antibodies and antichorionic gonadotropin antibodies. RESULTS: All THPs isolated by T&H; method from proteinuric patients were contaminated by IgG and one of the five preparations from pregnant women even by chorionic gonadotropin. A smaller or no contamination was found in THPs isolated by DEF method. CONCLUSIONS: Although albumin is the most abundant protein in the anomalous urine, it never appears in THP preparations. The consistent contamination with IgG of THP prepared by salt precipitation-method might be related to the formation of a stable complex between the two proteins. |
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