Protein Chemistry. Structure, Properties, Research Methods - Shendryk A.N. 2022

Proteins of Blood and Muscle Tissue
Proteins of the Contractile System
Functions of Muscle Tissue Proteins — Minor Muscle Proteins

Detailed studies of I-band components revealed that they contain yet another protein, troponin. It has been isolated and purified, with an MM of ≅ 86 kDa. Troponin forms a complex with Tropomyosin B. This complex, known as the “relaxing protein,” can bind to F-Actin to form a ternary complex: troponin – tropomyosin B – actin. One of the established Functions of troponin is its ability to tightly bind Calcium Ions. It is hypothesized to serve as the Ca2+-binding component in the troponin – tropomyosin B – actin – Myosin complex, triggering Muscle contraction upon the appearance of free calcium ions.

The minor Proteins of actin filaments likely include two additional proteins, α- and β-actinin. The first of these functions as a cross-linking protein, while the second appears to be associated with troponin.



Last update: 06/08/2026

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