title: Myosin light chain phosphorylation in intact human muscle.
abstract: The phosphate content of the fast (LC2F) and two slow (LC2S and LC2S1) phosphorylatable light chains (P-light chains) in myosin isolated from biopsy samples of rested human vastus lateralis muscle averaged 0.21, 0.28 and 0.25 mol of phosphate per mol of P-light chain, respectively. Following a 10 s maximal contraction, phosphate content was increased by almost 2-fold in the fast and two slow P-light chains. After prolonged, moderate cycling activity phosphate content was only slightly increased in the three P-light chains. These data suggest that, unlike animal skeletal muscle, myosin light chain kinase and phosphatase activities are similar in human fast and slow muscle fibres.
mesh_terms: D001707:Biopsy, Needle; D005260:Female; D006801:Humans; D007525:Isoelectric Focusing; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000378:metabolism*; D015879:Myosin Subfragments; D009218:Myosins / Q000302:isolation & purification / Q000378:metabolism*; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D005082:Physical Exertion
chemical_list: D015879:Myosin Subfragments; D010446:Peptide Fragments; D009218:Myosins