A comparative study of muscle contraction and superprecipitation using trinitrophenylated myosin and active myosin subfragments

Myosin and heavy meromyosin (HMM) were trinitrophenylated (TNP-ed) to different tents by 2,4,6-trinitro benzene sulfonate. Protein preparations in which only one active te per molecule has been TNP-ed were isolated by using immobilized ATP affinity chromatography columns. Irrigation of "ghost" myofibrils (i.e. myofibrils from which the myosin has been extracted) with either of these "one-headed" species, followed by the addition of ATP, caused contraction. The myosin derivative exhibited also superprecipitation. On the her hand, fully TNP-ed myosin and HMM could not induce contraction of ghosts and the rst did not give superprecipitation. The relationship between superprecipitation and scle contraction is discussed.