A careful search has been made for a covalently linked phosphoryl group in myosin which has cleaved one AT32P per mole in a "burst" reaction. No evidence for a phosphoryl myosin was obtained upon extraction of protein with phenol near neutral pH, or by measurement of l80 incorporation into inorganic phosphate (Pi) formed when trichloroacetic acid-H W H was used to stop adenosine triphosphate (ATP) hydrolysis. Further, with EDTA or phenol as stopping agents in the presence of H1*0H, lack of appreciable '80 incorporation into Pi does not support possible pres-
Physical exercise leads to many metabolic, cardiovascular, and muscular changes in the body. The trace elements (TE) zinc and copper are directly involved, as enzymatic cofactors, in many of these processes, especially those related to nutrients metabolism, oxygen transport, and formation of usable energy. The effects of high-intensity physical exercise on plasma levels of CU2+ and Zn2+ in 19 subjects are investigated (9 males and 10 females). Plasma copper concentration decreases, and plasma zinc concentration increases, after exercise, in both sexes. After 30 min recovery, both TE concentration values shifts toward rest values in both sexes. These results only partially agree with literature data, probably because we used the treadmill exercise, which makes many muscles work, whereas other authors made their subjects perform a cycloergometer exercise. Physical exercise causes a marked redistribution of TE (copper and zinc) between body stores, bloodstream, and tissues. The condition of high metabolism may lead to a deficiency of TE, requiring supplementation in order to maintain high level performance.
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