The hemolymph clottable proteins of tiger shrimp, Penaeus monodon, and related species

Abstract

A clottable protein was purified from the hemolymph of tiger shrimp ( Penaeus monodon) by sequential DEAE anion-exchange chromatography. The protein formed stable clots in the presence of Ca 2+ and the transglutaminase in hemocyte lysate. It is thermostable at temperatures up to 66°C. The molecular mass of the clottable protein was determined to be 380 kDa by SDS–PAGE and MALDI–TOF mass spectrometry, and the protein exists as disulfide-linked homodimers and oligomers. The size and amino acid composition of the clottable protein are similar to those of several other shrimps, prawns, lobster and crayfish, and their N-terminal amino acid sequences are 60–80% identical. Monosaccharide analysis of the clottable protein revealed the presence of mannose, glucosamine or N-acetylglucosamine and possibly glucose in this glycoprotein of about 5% sugar content. Lipid in the protein upon electrophoresis was hardly detectable with the Oil Red O staining method. In immunodiffusion and immunoblotting analyses, the anti-clottable protein antibodies reacted with the clottable proteins from the penaeid shrimps but not with those from other crustaceans.