Distribution of three isoforms of antimicrobial peptide, chrysophsin-1, -2 and -3, in the red sea bream, Pagrus (Chrysophrys) major.

We report here a liquid chromatography/electrospray ionization-tandem mass spectrometry assay for the quantification of three isoforms of antimicrobial peptide (AMP), chrysophsin-1, -2 and -3, in the red sea bream, Pagrus (Chrysophrys) major. Chrysophsin-1 was mainly distributed in the pyloric caeca and gills, followed by intestine and stomach. Chrysophsin-2 was detected in the gills and stomach, but chrysophsin-3 was only in the gills. The present procedure is valuable as a general method for simultaneous determination of the level of multiple AMP isoforms in fish tissues, and the data give important information for understanding the significance of each AMP isoform in host defense.