Denaturation and aggregation of myosin from two bovine muscle types.
The thermal behaviors of myosin from bovine vastus intermedius (VI, predominantly red muscle) and semimembranosus (SM, predominantly white muscle) at pH 6.05 (ultimate pH of VI muscle) and 5.50 (ultimate pH of SM muscle) were compared. Differential scanning microcalorimetry and turbidity measurements were used to monitor changes in myosin during heating from 25 to 80 degrees C at 1 degrees C/min. VI and SM myosin heavy chain isoforms were identified on gradient SDS-PAGE. Endotherms of VI myosin at pH 6.05 had three transition temperatures (T(m)) of 45, 53, and 57 degrees C, whereas at pH 5.50 two transitions were observed at 42 and 59 degrees C. SM myosin had two T(m) values of 46 and 58 degrees C at pH 6.05 and T(m) values of 43 and 62 degrees C at pH 5.5. SM myosin at its ultimate pH was less heat stable than VI myosin at its ultimate pH; however, when SM and VI myosin were compared at the same pH, VI myosin was less stable.
Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824-1224, USA.
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Vega-Warner
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Smith
D000818:Animals; D002152:Calorimetry, Differential Scanning; D002417:Cattle; D005260:Female; D006358:Hot Temperature; D018656:Muscle Fibers, Fast-Twitch / Q000737:chemistry; D018482:Muscle, Skeletal / Q000737:chemistry*; D009218:Myosins / Q000737:chemistry* / Q000302:isolation & purification; D009391:Nephelometry and Turbidimetry; D011489:Protein Denaturation; D020033:Protein Isoforms / Q000737:chemistry / Q000302:isolation & purification
D020033:Protein Isoforms; D009218:Myosins