スサビノリプロトプラストのタンパク質

抄録

To elucidate the properties of protein in red alga Prophyra yezoensis, protoplasts having lesser amount of polysaccharides were used as a starting material. Protoplasts were isolated from Por-phyra by pre-treatment with protease followed by wall digesting enzyme mixture consisting of abalone enzyme and Macerozyme R-l0. Proteins in protoplasts were then extracted with low (I=0.05) and high (I=0.5) ionic strength phosphate buffer (pH 7.5) and 0.1_N sodium hydroxide, and analyzed for protein composition, SDS-polyacrylamide gel electrophoretic pattern, and amino acid composition.
The average content of crude protein in protoplasts was 32.7%, the amount being 5% higher than that of the thallus. The major protein in the protoplasts was water-soluble protein and it amounts to 43.2% of total nitrogen. Salt-soluble protein was a minor fraction (3.1% of total nitrogen). Electrophoretic pattern of the protein fractions consisted of many bands, and that of the water-soluble protein fraction was closely similar to that of the corresponding fractions from the thallus. In contrast, the patterns of salt-soluble and alkali-soluble protein fractions were different between protoplasts and thallus. Amino acid composition, however, was similar in all protein fractions from both protoplasts and thallus. The proteins were rich in aspartic and glutamic acids, alanine and leucine, and poor in histidine and methionine.