scholarly journals Action of Dinitrophenyl Amino Acids on Skeletal Muscle Proteins. I. Weak and Strong Absorption of Bis(Dinitrophenyl)Lysine and Bis(Dinitrophenyl)Ornithine by Myosin

1967 ◽  
Vol 20 (5) ◽  
pp. 983
Author(s):  
RW Burley ◽  
WJH Jackson ◽  
Jean P Robertson

Below about 15�C in high ionic strength (0'5) phosphate buffer at neutral pH, the coloured compound bis(2,4.dinitrophenyl)-L-lysine (abbreviation bis-DNPlysine) was slowly but extensively absorbed from solution by rabbit skeletal muscle myosin. The absorption equations of Scatchard and of Klotz were not obeyed, thus suggesting that absorption did not involve independent sites. At higher temperatures, or if the myosin sulphydryl groups had been blocked with p-chloromercuribenzoate, absorption increased, often by as much as fivefold, and, moreover, a part of the absorbed bis-DNP-Iysine, probably corresponding to the "precipitation resistant" absorption reported previously, was strongly retained. Total absorption ofb~s-DNPlysine by myosin decreased slightly with increasing pH. At low temperatures bis-DNP-Iysine treatment induced the formation of small aggregates of myosin.

1969 ◽  
Vol 22 (1) ◽  
pp. 205
Author(s):  
RW Burley ◽  
Jean P Robertson

Isotherms for the total absorption ofbis(2,4-dinitrophenyl)-L-lysine (bis-DNP-lysine) by rabbit skeletal muscle myosin and heavy meromyosin whose sulphydryl groups had been progressively blocked with p-chloromercuribenzoate were measured by equilibrium dialysis in Tris buffers containing potassium chloride.


1968 ◽  
Vol 21 (1) ◽  
pp. 141
Author(s):  
RW Burley ◽  
WJH Jackson ◽  
Jean P Robertson

The quantity of bis(2,4-dinitrophenyl)-L-Iysine (abbreviation bis-DNP-Iysine) absorbed at 5�C by myosin and meromyosins of rabbit skeletal muscle was estimated in phosphate buffer (pH 7, ionic strength 0�5) by two methods, one based on equilibrium dialysis, the other on high-speed centrifugation. According to both methods, heavy meromyosin absorbed more of the reagent than did the same weight of the parent myosin; light meromyosin absorbed less, and light meromyosin fraction I absorbed less still. There were, however, relatively large quantitative differences between the two methods, possibly because of an effect of the slightly different conditions of treatment.


1975 ◽  
Vol 67 (1) ◽  
pp. 93-104 ◽  
Author(s):  
T D Pollard

Electron micrographs of negatively stained synthetic myosin filaments reveal that surface projections, believed to be the heads of the constituent myosin molecules, can exist in two configurations. Some filaments have the projections disposed close to the filament backbone. Other filaments have all of their projections widely spread, tethered to the backbone by slender threads. Filaments formed from the myosins of skeletal muscle, smooth muscle, and platelets each have distinctive features, particularly their lengths. Soluble mixtures of skeletal muscle myosin with either smooth muscle myosin or platelet myosin were dialyzed against 0.1 M KC1 at pH 7 to determine whether the simultaneous presence of two types of myosin would influence the properties of the filaments formed. In every case, a single population of filaments formed from the mixtures. The resulting filaments are thought to be copolymers of the two types of myosin, for several reasons: (a) their length-frequency distribution is unimodal and differs from that predicted for a simple mixture of two types of myosin filaments; (b) their mean length is intermediate between the mean lengths of the filaments formed separately from the two myosins in the mixture; (c) each of the filaments has structural features characteristic of both of the myosins in the mixture; and (d) their size and shape are determined by the proportion of the two myosins in the mixture.


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