A novel trypsin inhibitor from Peltophorum dubium seeds, with lectin-like properties, triggers rat lymphoma cell apoptosis

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• 作者：Fernanda Troncoso ; M. ; Cerdá ; Zolezzi ; Paula ; Hellman ; Ulf ; Wolfenstein-Todel ; Carlota
• 关键词：Kunitz-type trypsin inhibitor ; Lectin ; Apoptosis ; Lymphoma cells ; Peltophorum dubium
• 刊名：Archives of Biochemistry and Biophysics
• 出版年：2003
• 出版时间：March 1, 2003
• 年：2003
• 卷：411
• 期：1
• 页码：93-104
• 全文大小：1.63 M

文摘

A trypsin inhibitor (PDTI) was isolated from Peltophorum dubium seeds by affinity chromatography on a thyroglobulin–agarose or a trypsin–agarose column. In both cases, SDS–PAGE showed two bands of M_r 20,000 and 22,000, which could not be resolved. Their amino-terminal sequences were identical and similar to that of Kunitz-type soybean trypsin inhibitor (SBTI). Mass spectrometry analysis of tryptic digests of both bands showed 16 coincident peaks, suggesting that they are closely related proteins. The K_is for trypsin and chymotrypsin inhibitory activity of PDTI were 1.6×10⁻⁷ and 1.3×10⁻⁵M, respectively. Lectin-like activity of PDTI and SBTI, detected by hemagglutination of rabbit erythrocytes, was inhibited by sialic acid-containing compounds. PDTI and SBTI caused apoptosis of Nb2 rat lymphoma cells, demonstrated by decrease of viability, DNA hypodiploidy, DNA fragmentation, and caspase-3-like activity. They had no effect on normal mouse splenocytes or lymphocytes, whereas they caused apoptosis of concanavalin A-stimulated mouse lymphocytes.