Lactate dehydrogenase-induced conformational changes of F-actin in myosin-free ghost single fibres.
The changes in conformation of F-actin induced by the binding of the glycolytic enzyme lactate dehydrogenase were studied in myosin-free single ghost muscle fibres. The formation of the lactate dehydrogenase-F-actin complex was accompanied by changes in the parameters of intrinsic (tryptophan) and extrinsic (rhodaminyl-phalloin) polarized fluorescence of ghost muscle fibre F-actin. Lactate dehydrogenase stimulated actin-activated Mg2+-ATPase of myosin subfragment 1 by 30%. F-actin of ghost fibres depressed lactate dehydrogenase activity to 20% of the initial values. It is suggested that the energy-providing mechanism is coupled with that of muscle contraction through conformational changes in F-actin.
Kirillina
V P
VP
Institute of Cytology, Academy of Sciences of the USSR, Leningrad.
Stabrovskaya
V I
VI
Borovikov YuS
D000199:Actins / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D004734:Energy Metabolism; D005454:Fluorescence Polarization; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism / Q000494:pharmacology*; D009119:Muscle Contraction; D009132:Muscles / Q000187:drug effects / Q000502:physiology; D015879:Myosin Subfragments / Q000378:metabolism; D009218:Myosins / Q000378:metabolism; D011487:Protein Conformation / Q000187:drug effects; D011817:Rabbits
D000199:Actins; D015879:Myosin Subfragments; D007770:L-Lactate Dehydrogenase; D017301:Ca(2+) Mg(2+)-ATPase; D009218:Myosins