scholarly journals Action of Dinitrophenyl Amino Acids on Skeletal Muscle Proteins

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.

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.


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.


1988 ◽  
Vol 107 (6) ◽  
pp. 2213-2221 ◽  
Author(s):  
C S Johnson ◽  
N M McKenna ◽  
Y Wang

Purified skeletal muscle myosin was labeled with iodoacetamidofluorescein and microinjected into cultured chick myotubes. The fluorescent myosin analogue became incorporated within 10-15 min after injection, into either periodic (mean periodicity = 2.23 +/- 0.02 micron) bands or apparently continuous fibrillar structures. Comparison of rhodamine-labeled alpha-actinin with coinjected fluorescein-labeled myosin suggested that myosin fluorescence was localized at the A-bands of myofibrils. In addition, close examination of the fluorescent myosin bands indicated that they were composed of two fluorescent bars separated by a nonfluorescent line that corresponded to the H-zone. Once incorporated, the myosin underwent a relatively slow exchange along myofibrils as indicated by fluorescence recovery after photobleaching. Glycerinated myofibrils were able to bind fluorescent myosin in a similar pattern in the presence or absence of MgATP, indicating that actin-myosin interactions had little effect on this process. Fluorescent heavy meromyosin did not incorporate into myofibrillar structures after injection. Light meromyosin, however, associated with A-bands as did whole myosin. These results suggest that microinjected myosin, even with its relatively low solubility under the cytoplasmic ionic condition, is capable of association with physiological structures in living muscle cells. Additionally, the light meromyosin portion of the molecule appears to be mainly responsible for the incorporation.


1992 ◽  
Vol 288 (3) ◽  
pp. 733-739 ◽  
Author(s):  
S J Winder ◽  
C Sutherland ◽  
M P Walsh

Thiosphosphorylated smooth muscle myosin and skeletal muscle myosin, both of which express Ca(2+)-independent actin-activated MgATPase activity, were used to examine the functional effects of calponin and caldesmon separately and together. Separately, calponin and caldesmon inhibited the actin-activated MgATPase activities of thiophosphorylated smooth muscle myosin and skeletal muscle myosin, calponin being significantly more potent in both systems. Calponin-mediated inhibition resulted from the interaction of calponin with actin since it could be reversed by increasing the actin concentration. Caldesmon had no significant influence on the calponin-induced inhibition of the smooth muscle actomyosin ATPase, nor did calponin have a significant effect on caldesmon-induced inhibition. In the skeletal muscle system, however, caldesmon was found to override the inhibitory effect of calponin. This difference probably reflects the lower affinity of skeletal muscle actin for calponin compared with that of smooth muscle actin. Calponin inhibition of skeletal muscle actin-activated myosin MgATPase was not significantly affected by troponin/tropomyosin, suggesting that the thin filament can readily accommodate calponin in addition to the troponin complex, or that calponin may be able to displace troponin. Calponin also inhibited acto-phosphorylated smooth muscle heavy meromyosin and acto-skeletal muscle heavy meromyosin MgATPases. The most appropriate protein preparations for analysis of the regulatory effects of calponin in the actomyosin system therefore would be smooth muscle actin, tropomyosin and thiophosphorylated myosin, and for analysis of the kinetic effects of calponin on the actomyosin ATPase cycle they would be smooth muscle actin, tropomyosin and phosphorylated heavy meromyosin, due to the latter's solubility.


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