Determination of sulphate and uronic acid in glycosaminoglycans of human dermis and in urine

Abstract

Special methods for the preparation of glycosaminoglycans (GAG) in human dermal tissue and in urine have been developed, enabling in the same preparation the determination of uronic acids as well as the bound organic sulphate without previous use of time-consuming procedures for purification. Special concern has been devoted to the effect of the papain digestion on the recovery of organic sulphate from dermal tissue, and the tissue procedure is further characterized with respect to disintegration, fat extraction and acid hydrolysis. It is shown that human urinary GAG, prepared by the short procedure described, demands a more effective HCI-hydrolysis of organic sulphate than proposed in the literature dealing with purified preparations of GAG. Besides a decrease in the release of sulphate, ineffective hydrolysis may also cause interference in the final sulphate assay, resulting in falsely increased values. It is shown that proteinuria exceeding 0.5 g/l causes a decrease in precipitation yield of GAG and the sulphate/uronic acid ratio. The procedure has resulted in methods of satisfactory accuracy and precision, and due to their large capacity the methods make it possible to get reliable information about the degree of sulphation in dermal and urinary GAG at different conditions in all diseases.

Key Words:

• acid hydrolysis
• chondroitin sulphate
• collagen
• fat extraction
• GAG-precipitation
• Heparin
• N-sulphate
• O-sulphate
• papain
• proteinuria
• tissue disintegration
• urinary proteins