Activating Compound | Comment | Organism | Structure |
---|---|---|---|
F-actin | myosin Mg-ATPase of molluscan muscles is slightly activated by F-actin under catch state in vitro. At low Ca2+ concentration, Mg-ATPase is activated by F-actin only in the presence of dephosphorylated twitchin, a titin/connectinrelated giant protein, regulates interactions between actin and myosin filaments at low Ca2+ concentrations. When it is dephosphorylated, actin filaments tightly bind to myosin filaments, resulting in the catch state known as the state of high passive tension with very low energy consumption. In the absence of twitchin, F-actin does not bind to myosin filaments | Mytilus galloprovincialis |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | steady-state Mg-ATPase activities of purified myosin, overview | Mytilus galloprovincialis |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Ca2+ | activates the Mg-ATPase activity of myosin | Mytilus galloprovincialis | |
Mg2+ | required | Mytilus galloprovincialis |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + H2O + myosin bound to actin filament at position n | Mytilus galloprovincialis | - |
ADP + phosphate + myosin bound to actin filament at position n+1 | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Mytilus galloprovincialis | - |
- |
- |
Purification (Comment) | Organism |
---|---|
native myosin from smooth adductor muscle | Mytilus galloprovincialis |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
smooth adductor muscle | - |
Mytilus galloprovincialis | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + H2O + myosin bound to actin filament at position n | - |
Mytilus galloprovincialis | ADP + phosphate + myosin bound to actin filament at position n+1 | - |
? |
Synonyms | Comment | Organism |
---|---|---|
myosin Mg-ATPase | - |
Mytilus galloprovincialis |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
25 | - |
assay at | Mytilus galloprovincialis |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7 | - |
assay at | Mytilus galloprovincialis |
General Information | Comment | Organism |
---|---|---|
physiological function | myosin Mg-ATPase of molluscan muscles is slightly activated by F-actin under catch state in vitro. At low Ca2+ concentration, Mg-ATPase is activated by F-actin only in the presence of dephosphorylated twitchin, a titin/connectinrelated giant protein, regulates interactions between actin and myosin filaments at low Ca2+ concentrations. When it is dephosphorylated, actin filaments tightly bind to myosin filaments, resulting in the catch state known as the state of high passive tension with very low energy consumption. When twitchin is phosphorylated actin filaments detach from the myosin filaments, resulting in relaxation of the catch. In the absence of F-actin, twitchin and its phosphorylation state do not affect Mg-ATPase activities in any of the conditions tested. Determination of a molecular mechanism for the catch, where twitchin alone does not interact with the myosin catalytic motor domain but its complex with F-actin does, forming the bridge between actin and myosin filaments and the myosin slowly hydrolyzes Mg-ATP in the catch state. Regulation mechanism, overview | Mytilus galloprovincialis |