Comparison of the structure of two cardiac troponin T isoforms.
Two isoforms of troponin T have been isolated from bovine cardiac muscle. One isoform has an Mr of 31000 and a pI at about 7.1, the corresponding values for the second isoform being 33000 and 6.5. Both isoforms have identical C- and N-terminal sequences, and, according to the data from tryptic-peptide mapping, a similar structure of the central and C-terminal domains. The large N-terminal peptides of troponin T isoforms differ in the content of glutamine/glutamic acid and alanine. It is concluded that the isoform with Mr 33000 has an additional peptide enriched with glutamic acid and alanine that is inserted between the N-terminal pentapeptide and the cysteine located 40-60 residues from the N-terminus.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D007536:Isomerism; D008970:Molecular Weight; D009206:Myocardium / Q000032:analysis*; D014336:Troponin; D020107:Troponin T; D014357:Trypsin
D000596:Amino Acids; D014336:Troponin; D020107:Troponin T; D014357:Trypsin