title: Phosphorylation in vivo of the P light chain of myosin in rabbit fast and slow skeletal muscles.
abstract: The P light chain of myosin is partially phosphorylated in resting slow and fast twitch skeletal muscles of the rabbit in vivo. The extent of P light-chain phosphorylation increases in both muscles on stimulation. Rabbit slow-twitch muscles contain two forms of the P light chain that migrate with the same electrophoretic mobilities as the two forms of P light chain in rabbit ventricular muscle. The rate of phosphorylation of the P light chain in slow-twitch muscle is slower than its rate of phosphorylation in fast-twitch muscles during tetanus. The rate of P light-chain dephosphorylation is slow after tetanic contraction of fast-twitch muscles in vivo. The time course of dephosphorylation does not correlate with the decline of post-tetanic potentiation of peak twitch tension in rabbit fast-twitch muscles. The frequency of stimulation is an important factor in determining the extent of P light-chain phosphorylation in fast- and slow-twitch muscles.
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D004586:Electrophoresis; D005260:Female; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism*; D010766:Phosphorylation; D011817:Rabbits; D013997:Time Factors
chemical_list: D009218:Myosins