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Evidence-Based Complementary and Alternative Medicine
Volume 2011, Article ID 851396, 12 pages
http://dx.doi.org/10.1155/2011/851396
Research Article

Antitumor and HIV-1 Reverse Transcriptase Inhibitory Activities of a Hemagglutinin and a Protease Inhibitor from Mini-Black Soybean

School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin New Territories, Hong Kong

Received 20 May 2010; Revised 18 October 2010; Accepted 10 January 2011

Copyright © 2011 Xiu Juan Ye and Tzi Bun Ng. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Protease inhibitors (PIs) and hemagglutinins are defense proteins produced by many organisms. From Chinese mini-black soybeans, a 17.5-kDa PI was isolated using chromatography on Q-Sepharose, SP-Sepharose, and DEAE-cellulose. A 25-kDa hemagglutinin was purified similarly, but using Superdex 75 instead of DEAE-cellulose in the final step. The PI inhibited trypsin and chymotrypsin (IC50 = 7.2 and 8.8 μM). Its trypsin inhibitory activity was stable from pH 2 to pH 13 and from 0C to 70C. The hemagglutinin activity of the hemagglutinin was stable from pH 2 to pH 13 and from 0C to 75C. The results indicated that both PI and hemagglutinin were relatively thermostable and pH-stable. The trypsin inhibitory activity was inhibited by dithiothreitol, signifying the importance of the disulfide bond to the activity. The hemagglutinating activity was inhibited most potently by D (+)-raffinose and N-acetyl-D-galactosamine, suggesting that the hemagglutinin was specific for these two sugars. Both PI and hemagglutinin inhibited HIV-1 reverse transcriptase (IC50 = 3.2 and 5.5 μM), proliferation of breast cancer cells (IC50 = 9.7 and 3.5 μM), and hepatoma cells (IC50 = 35 and 6.2 μM), with relatively high potencies.