Screening of Antithrombotic Peptides from Soybean Paste by the Microplate Method

Abstract

In order to search for antithrombotic peptides from soybean paste, the inhibitory activity of water extract of soybean paste and its peptide fractions on ADP-induced aggregation of washed platelets was assayed. Soybean paste extract treated with ultrafiltration (M.W. cut off, 3,000 daltons) was found to have inhibitory activity of 90% at the dose of by the method of turbidometric aggregometer. Soybean paste extract was fractionated to 19 fractions (No. B-18) by Dowex 50W X-2 ion exchange column chromatography and activity test was performed by the microplate method. All of the fractions had antithrombotic activity , and most fractions had higher activity than positive control, RGDS . Especially, basic fractions No.16-18 showed higher activity than soybean paste extract . The fraction No.16 with the highest activity was purified and analysed for amino acid composition. The results showed that histidine, arginine, and alanine were major residues in the peptide part of the fraction.