Lys515-Lys492 cross-linking by DIDS interferes with substrate utilization by the sarcoplasmic reticulum ATPase
Related Experiment Video
Updated: Oct 31, 2026

Purification of the Sarco-Endoplasmic Reticulum Ca2+-ATPase from Rabbit Muscle
Published on: March 21, 2025
1Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore 21201, USA.
Abstract:
Sarcoplasmic reticulum (SR) Ca2+ ATPase was derivatized with 4,4'-diisothiocyanatostilbene-2,2'-sulfonic acid (DIDS), and complete enzyme inactivation was produced with a molecular stoichiometry of one DIDS per ATPase. It was determined by peptide analysis and sequencing that Lys492 and Lys515 were the ATPase residues derivatized by DIDS. Lack of electrophoretic resolution of the two peptide fragments that result from a single tryptic cut at Arg505 demonstrated that the two derivatized residues were cross-linked. Cross-linking of Lys492 and Lys515 by DIDS interfered with ATPase utilization of both ATP and p-nitrophenyl phosphate substrates, whereas derivatization of only Lys515 with fluorescein isothiocyanate interfered with ATPase utilization of ATP but not of p-nitrophenyl phosphate. Cross-linking with DIDS implies a distance of approximately 13 A between Lys492 and Lys515, which corresponds to the length of ATP bound in an extended configuration. Therefore, within the groove of the nucleotide binding domain, the ATP substrate is positioned with the adenosine moiety near Lys515 and its terminal phosphate near Lys492.
Related Concept Videos
ATP Synthase: Mechanism
The Electron Transport Chain
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
ATP Synthase: Structure
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Muscle Recovery and Fatigue
Lysosomal Hydrolases

