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Updated: Jun 1, 2026

Purification of the Sarco-Endoplasmic Reticulum Ca2+-ATPase from Rabbit Muscle
Published on: March 21, 2025
Tropomyosin is in a reduced state in rabbit psoas muscle
Sherwin S Lehrer1, Socheata Ly, Franklin Fuchs
1Cardiovascular Program, Boston Biomedical Research Institute, Watertown, MA 02472, USA. Lehrer@BBRI.org
Abstract:
Tropomyosin (Tm) purified from skeletal and cardiac muscle often contains disulfide bonds due to oxidation of cysteine groups that are in close proximity in the coiled-coil structure. Are these disulfide crosslinks present in the muscle or produced by oxidation during preparation? To answer this question we reacted one part of freshly dissected rabbit psoas muscle fibers, which was permeabilized with Triton X-100, with N-ethyl maleimide (NEM) to block cysteine groups and another part with 5,5'-dithiobis(2-nitro benzoate) (DTNB) to facilitate disulfide bond formation by interchain sulfhydryl-disulfide exchange. We found, by high resolution gradient SDS polyacrylamide gels, that the NEM-treated muscle was only composed of uncrosslinked Tm and the DTNB treated muscle was composed of disulfide-crosslinked Tm. This work indicates that Tm exists in a reduced state in rabbit psoas muscle.
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