Linaclotide Impurity 51 (Cyclic (1-5), (2-6) . (10-13) -tris (disulfide) )

((4R,10S,13R) -13- ((S) -2- (((S) -2- ((S) -5-amino-3- ((1R,4S,7S,10R,13R,20R) -13-amino-7- (2-carboxyethyl) -4- (4-hydroxybenzyl) -3,6,9,12,18-pentaoxo-15,16,22,23-tetrathia-2,5,8,11,19-pentaazabicyclo[8.7.7]tetracosane-20-carboxamido) -2,5-dioxopentanoyl) pyrrolidin-1-yl) amino) propanamido) -10- ((R) -1-hydroxyethyl) -6,9,12-trioxo-1,2-dithia-5,8,11-triazacyclotetradecane-4-carbonyl) -L-tyrosine