Proteins in Three Seaweeds, “Aosa” Ulva lactuca, “Arame” Eisenia bicyclis, and “Makusa” Gelidium amansii

Aosa” Ulva lactuca (green alga), “arame” Eisenia bicyclis (brown alga), and “makusa” Gelidium amansii (red alga) were extracted with KCl-phosphate buffer (I=0.5, pH 7.5), and fractionated with ammonium sulfate. Nitrogen distribution was higher in 0-20% saturation fraction for aosa, in >80% saturation fraction for arame, and 40-60% saturation fraction for makusa. The extracts of aosa and arame contained nonprotein nitrogen up to 34% of the total nitrogen, in contrast to that of makusa 13%. Each of the water-soluble, salt-soluble, and alkali-soluble protein fractions accounted for less than 10% of the total nitrogen through the three seaweeds. Irrespective of the species, the three protein fractions were rich in aspartic and glutamic acids, glycine and alanine, and poor in methionine, tyrosine and histidine.