Myosin II protein: rabbit skeletal muscle

Myosin II protein: rabbit skeletal muscle

Product Uses Include

  • Measurement of F-actin activated myosin ATPase activity
  • Identification/characterization of proteins or small molecules that affect myosin II ATPase activity
  • Identification/characterization of proteins or small molecules that affect the myosin II - F-actin interaction
  • Control myosin ATPase activity in drug discovery screening projects

Myosin II protein has been purified from rabbit skeletal muscle. The full length myosin II protein has been purified with its essential light chains (ELC) and regulatory light chains (RLC), see Figure 1 and 2. Myosin II has been determined to be biologically active in an F-actin activated ATPase assay. Rabbit skeletal muscle myosin II is not recommended for use in motility assays. Rabbit myosin II protein is supplied as a white lyophilized powder. When reconstituted in nanopure water, the protein will be in the following buffer: 25 mM PIPES-NaOH pH 7.0, 1.25 M KCl, 2.5% sucrose and 0.5% dextran. The lyophilized protein is stable at 4°C desiccated (<10% humidity) for 1 year.


Figure 1. Diagrammatic representation of the myosin II protein and its subfragments. Myosin II or conventional myosin is a hexameric protein consisting of two heavy chains and two light chains. Myosin II can be proteolytically cleaved into heavy meromyosin (HMM, Cat.# MH01) and light meromyosin (LMM) by α-chymotrypsin. Heavy meromyosin consists of the myosin head subfragment-1 domain (S1), its associated light chains (essential light chains and regulatory light chains), and the coiled-coil subfragment -2 domain. Light meromyosin consists of coiledcoil protein structure. The myosin S1-subfragment is produced by papain digestion of HMM.

Protein purity is determined by scanning densitometry of Coomassie Blue stained protein on a 4-20% gradient polyacrylamide gel. Myosin protein is 90% pure (see Figure 2).


 Figure 2. Myosin II protein purity determination. A 20 µg sample of MY02 was separated by electrophoresis in a 4-20% SDS-PAGE system, and stained with Coomassie Blue. Arrow indicates the myosin heavy chain (approx. 200 kDa), arrowheads indicate the RLC (approx. 20 kDa) and two ELC isoforms (approx. 25 and 17 kDa). Protein quantitation was performed using the Precision Red Protein Assay Reagent (Cat.# ADV02).

Biological Activity
The biological activity of rabbit myosin II is determined from its rate of F-actin activated ATP hydrolysis. A standard biological assay for monitoring ATP hydrolysis by myosin consists of an in vitro F-actin ATPase assay (Cat. # BK054). Stringent quality control ensures that in the presence of F-actin, rabbit myosin will have a minimum hydrolysis rate 10 fold greater than in the absence of F-actin, which is comparable to published results.

For product Datasheets and MSDSs please click on the PDF links below.   For additional information, click on the FAQs tab above or contact our Technical Support department at

Bulk Size Datasheet (Cat. MY02-XL):  

AuthorTitleJournalYearArticle Link
Sakamoto, Ryota et al.F-actin architecture determines the conversion of chemical energy into mechanical workNature Communications 2024 15:12024ISSN 2041--1723
Henry, Conor M. et al.SYK ubiquitination by CBL E3 ligases restrains cross-presentation of dead cell-associated antigens by type 1 dendritic cellsCell reports2023ISSN 2211--1247
Al Azzam, Omayma et al.Probing Myosin Ensemble Mechanics in Actin Filament Bundles Using Optical TweezersJoVE (Journal of Visualized Experiments)2022ISSN 1940--087X
Sasanpour, Mehrzad et al.Reconstituting and Characterizing Actin-Microtubule Composites with Tunable Motor-Driven Dynamics and MechanicsJoVE (Journal of Visualized Experiments)2022ISSN 1940--087X
Bashirzadeh, Yashar et al.Encapsulated actomyosin patterns drive cell-like membrane shape changesiScience2022
Sheung, Janet Y. et al.Motor-driven advection competes with crowding to drive spatiotemporally heterogeneous transport in cytoskeleton compositesFrontiers in Physics2022
Giampazolias, Evangelos et al.Secreted gelsolin inhibits DNGR-1-dependent cross-presentation and cancer immunityCell2021ISSN 1097-4172
Lee, Gloria et al.Myosin-driven actin-microtubule networks exhibit self-organized contractile dynamicsScience Advances2021ISSN 2375-2548
Lee, Gloria et al.Active cytoskeletal composites display emergent tunable contractility and restructuringSoft Matter2021ISSN 1744-6848
Radnai, Laszlo et al.A semi-high-throughput adaptation of the nadh-coupled atpase assay for screening small molecule inhibitorsJournal of Visualized Experiments2019ISSN 1940-087X
Cervero, Pasquale et al.Lymphocyte-specific protein 1 regulates mechanosensory oscillation of podosomes and actin isoform-based actomyosin symmetry breakingNature Communications2018ISSN 2041-1723
Ehrlicher, A. J. et al.Mechanical strain in actin networks regulates FilGAP and integrin binding to filamin ANature 2011 478:73682011ISSN 1476--4687
Rao, Mala V. et al.The myosin Va head domain binds to the neurofilament-L rod and modulates endoplasmic reticulum (ER) content and distribution within axonsPLoS ONE2011ISSN 1932-6203
Harris, Elizabeth S. et al.The Mouse Formin, FRLα, Slows Actin Filament Barbed End Elongation, Competes with Capping Protein, Accelerates Polymerization from Monomers, and Severs FilamentsJournal of Biological Chemistry2004ISSN 0021-9258
Gallo, Gianluca et al.Actin turnover is required to prevent axon retraction driven by endogenous actomyosin contractility2002PMID 12356866


Question 1:  Does this myosin contain both light and heavy chains and all other subunits?

Answer 1:  Yes, this protein is full length myosin motor protein isolated from rabbit skeletal muscle.  The myosin protein contains the two heavy chains and two light chains, the essential light chain (ELC) and regulatory light chain (RLC).


Question 2:  Does this myosin have ATPase activity that is activated by actin filaments?

Answer 2:  Yes, the biological activity test for the myosin protein is in vitro measurement of myosin’s ATPase activity in the activating presence of actin filaments.  Stringent quality control ensures that in the presence of F-actin, rabbit skeletal muscle myosin will have a minimum hydrolysis rate 10 fold greater than in the absence of F-actin.



If you have any questions concerning this product, please contact our Technical Service department at