Study of the structure of troponin-C by measuring the relative reactivities of lysines with acetic anhydride.

摘要: Abstract The structure of troponin-C † has been studied by measuring the relative reactivity lysines with acetic anhydride using a competitive labeling method. Troponin-C was acetylated free and complexed troponin-I -T in native state [3H]acetic combined [14C]troponin-C that had 6 m -guanidine · HCl. Peptides containing labeled were isolated following chymotryptic tryptic digestion identified published sequence. 3 H 14 C ratio these peptides used as measure accessibility lysines. contains 9 lysine residues. In Lys20 least reactive Lys153 most reactive; remaining 7 intermediate reactivities. Lys52 more presence 10−5 -Ca2+ than 0.2 -EGTA (+2 -MgCl2). When troponin complex, 153 reactive, respectively. Lys52, (84, 88, 90) (136, 140) reduced to Lys37 153, suggesting regions are involved binding other components. reactivities influenced calcium ion concentration. A similar pattern seen when complex formation troponin-T resulted 90). results related structural studies predicted three-dimensional based on carp parvalbumin.