in view of the simple amino acid composition of salmon egg polysialoglycoprotein ( molar ratio asp2thr2ser3glu1pro1gly1ala3 ) and the result of alkaline beta-elimination indicating three carbohydrate units linked to two of two threonine and one of three serine residues , a unique primary structure comprising repetitive sequences of the above two types of glycopeptides , which are interspersed by short nonglycosylated peptides consisting of alanine and aspartic acid , has been proposed for the core protein .
C0002520
amino acid
C0001898
alanine