MUSCLE PHYSIOLOGY

Detailed explanation-1: -Troponin is attached to the protein tropomyosin and lies within the groove between actin filaments in muscle tissue. In a relaxed muscle, tropomyosin blocks the attachment site for the myosin crossbridge, thus preventing contraction. Tropomyosin needs to be displaced from this attachment for contraction to occur.

Detailed explanation-2: -In vertebrate striated muscle, troponin-tropomyosin is responsible, in part, not only for transducing the effect of calcium on contractile protein activation, but also for inhibiting actin and myosin interaction when calcium is absent.

Detailed explanation-3: -Tropomyosin and troponin prevent myosin from binding to actin while the muscle is in a resting state.

Detailed explanation-4: -A good example is cAMP-dependent protein kinase, which is composed of two regulatory and two catalytic subunits (Figure 7.38). In this state, the enzyme is inactive; the regulatory subunits inhibit the enzymatic activity of the catalytic subunits.

Detailed explanation-5: -regulatory protein (gene-regulatory protein) Any protein that influences the regions of a DNA molecule that are transcribed by RNA polymerase during the process of transcription. These proteins, which include transcription factors, therefore help control the synthesis of proteins in cells. A Dictionary of Biology.