Journal of Applied Phycology

, 9:331

The marine red alga Eucheuma serra J. Agardh, a high yielding source of two isolectins


  • Akihiro Kawakubo
    • Marine Greens Laboratory Co.
  • Hiroyuki Makino
    • Marine Greens Laboratory Co.
  • Jun-ichi Ohnishi
    • Marine Greens Laboratory Co.
  • Hideo Hirohara
    • Department of Materials ScienceThe University of Shiga Prefecture
  • Kanji Hori
    • Faculty of Applied Biological ScienceHiroshima University

DOI: 10.1023/A:1007915006334

Cite this article as:
Kawakubo, A., Makino, H., Ohnishi, J. et al. Journal of Applied Phycology (1997) 9: 331. doi:10.1023/A:1007915006334


Aqueous ethanolic extracts from five species of the genus Eucheuma (Rhodophyta) i.e. E. serra, E. amakusaensis, E. cottonii, E. gelatinae and E. denticulatum, were examined for hemagglutinating activity with vertebrate erythrocytes. All the extracts tested agglutinated trypsin-treated sheep and rabbit erythrocytes as well as untreated sheep erythrocytes. From the extract of E. serra, which exhibited the highest activity, a lectin was purified by precipitation with cold ethanol followed by gel filtration to exhibit a single band on SDS-PAGE. The yield was surprisingly as high as 1000 mg from 100 g powdered alga. The purified lectin was further separated into two isoforms, designated ESA-1(90 mg) and ESA-2 (890 mg), by ion exchange chromatography. Both lectins showed a single protein band with the same molecular weight of 29 000 on SDS-PAGE and differed from each other only in isoelectric point (pI 4.75 for ESA-1 and pI 4.95 for ESA-2). Biochemical studies revealed that both are monomeric proteins without a carbohydrate moiety. The hemagglutinating activities were stable over a wide pH range and at a relatively high temperature. The activities were inhibited by a number of glycoproteins, but not by any of the monosaccharides and disaccharides tested. The lectins showed strong mitogenic activities for mouse lymphocytes.

Eucheuma serrahemagglutininlectinisolectinmitogenic activitycarbohydrate-binding specificity
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© Kluwer Academic Publishers 1997