Analysis of protease digestion patterns in tideland sediments using SDS-PAGE

Abstract

A method to analyse protein hydrolysis in tideland sediments was developed using sodium lauryl sulphate (SDS)-polyacrylamide gel electrophoresis (PAGE). Bovine serum albumin was used as a substrate and sonication in SDS solution was employed to extract hydrolysed peptides from tideland sediments. By combining these techniques, digested peptides were fractionated reliably on slab gels by SDS-PAGE. Using this method, the protease activities in a tideland were found to be distributed only in the sediment fraction and not in the seawater. The protease activities in sediments were compared among three tidelands in the Seto Inland Sea. Niho tideland, the most polluted of the three tidelands examined, showed the highest levels of protease activity. Peptide cleavage patterns were very similar among the tidelands despite the differences in levels of protease activity, suggesting that the tidelands all contain common types of protease. Furthermore, the properties of proteases in tideland sediments were also characterised using the present method.