Identification of a cross‐linked double‐peptide from the catalytic site of the Ca 2+ ‐ATPase of sarcoplasmic reticulum formed by the Ca 2+ ‐ and pH‐dependent reaction with ATP γ P ‐imidazolidate

• Published in: FEBS letters Vol. 324; no. 3; pp. 314 - 318
• Main Authors: Gutowski-Eckel, Zeynep, Mann, Karlheinz, Bäumert, Hans G.
• Format: Journal Article
• Language: English
• Published: 21.06.1993
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(93)80142-H

The Ca 2+ ‐ATPase from sarcoplasmic reticulum can be inhibited by the Ca 2+ ‐ and pH‐dependent reaction with ATP γP‐imidazolidate. The chemically and monofunctionally activated inhibitor introduces an intramolecular cross‐link between two neighbouring peptides of the active site. This can be followed by the reduced mobility of the ATPase upon SDS‐PAGE analysis which becomes even more pronounced after limited trypsinolysis. After cleavage of the cross‐linked ATPase molecule by cyanogen bromide and separation of the peptides a double‐peptide can be detected which upon sequencing can be identified as part of the phosphorylation and the nucleotide binding site, respectively.