Titin
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| Sliding filament model of muscle contraction. (Titin labeled at upper right.) |
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Titin
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| Identifiers |
| Symbol |
TTN |
| Entrez |
7273 |
| HUGO |
12403 |
| OMIM |
188840 |
| RefSeq |
NM_133378 |
| UniProt |
Q8WZ42 |
| Other data |
| Locus |
Chr. 2 q31 |
Titin, also known as connectin[1] (UniProt name: Q10466_HUMAN; accession number: Q10466), is a protein that is important in the contraction of striated muscle tissues.
Structure
Titin is the largest known protein, consisting of 26,926 amino acids. The molecular weight of the mature protein is approximately 2,993,451.39 Da, and it has a theoretical pI of 6.01[2] The protein's empirical chemical formula is C132983H211861N36149O40883S693. It has a theoretical instability index (II) of 39.69, indicating that it would be stable in a test tube. The protein's in vivo half-life, the time it takes for half of the amount of protein in a cell to disappear after its synthesis in the cell, is predicted to be approximately 30 hours (in mammalian reticulocytes).[3]
Linguistic significance
As the largest known protein, titin has the longest full chemical name. The full chemical name, containing 189,819 letters, is sometimes stated to be the longest word in the English language.
References
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Histology: muscle tissue |
| skeletal muscle/general |
epimysium, fascicle, perimysium, endomysium, muscle fiber (intrafusal, extrafusal), myofibril
sarcomere (a, i, and h bands; z and m lines), myofilaments (thin filament/actin, thick filament/myosin, elastic filament/titin, nebulin), tropomyosin, troponin (T, C, I)
costamere (dystrophin, α,β-dystrobrevin, syncoilin, synemin/desmuslin, dysbindin, sarcoglycan, dystroglycan, sarcospan), desmin
neuromuscular junction, motor unit, muscle spindle, excitation-contraction coupling, sliding filament mechanism
myoblast, satellite cell, sarcoplasm, sarcolemma, sarcoplasmic reticulum, T-tubule |
| cardiac muscle |
myocardium, intercalated disc, nebulette |
| smooth muscle |
calmodulin, vascular smooth muscle |
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