Abstract
The authors have previously found tha two moles of lysine residues in one mole o myosin and H-meromyosin react specificall with TBS, and that S-1, the main componen of Fr-2, prepared from a trypsin digest of myosin, retains the intact active site of myosin-ATPase but contains only one mole of specific lysine per mole of S-1. Therefore, the chemical structures around the lysine residues specific to TBS in myosin, H-meromyosin and Fr-2 were compared.
TNP-protein was digested with Nagarse (1/20 of the weight of protein) and Pronase-P (1/20 of the weight of protein) and the TNP-peptide mixture was isolated with an IRC-50 column. The TNP-peptide mixture was sepa-rated into six fractions by paper chromato-graphy with n-butanol-tert-amyl alcohol-py-ridine-conc. NH4OH-acetic acid-H2O as solvent. From analysis of fractions II and VI in the six fractions it was demonstrated that about 50 per cent of the TNP-peptides isolated from TNP-Fr-2 was an equimolar mixture of Asp (NH2)-Pro-Pro-TNP-Lys and Pro-Pro-TNP-Lys and that the majority of the rest was TNP-lysine, itself. The yields of Asp (NH2)-Pro-Pro-TNP-Lys from TNP-myosin and TNP-H-meromyosin were smaller than that from TNP-Fr-2. Furthermore, it was shown that Pronase-P can release TNP-lysine from Asp (NH2)-Pro-Pro-TNP-Lys.
Therefore, it was concluded that the chemical structure around the lysine residue specific to TBS in Fr-2, i.e. the lysine located near the active site, is Asp(NH2)-Pro-Pro-Lys, but H-meromyosin contains another lysine residue specific to TBS, which was suggested to be the one in Ser-TNP-Lys-(Gly, Glu, Ser)-(Gly, Ala).
