ATP utilization for calcium uptake and force production in different types of human skeletal muscle fibres

• DOI: 10.1111/j.1469-7793.2001.0393i.x
• Publication Date: 2004-08-05T11:03:39Z
• Authors: P. Szentesi; R. Zaremba; W. van Mechelen; G. J. M. Stienen
• Keywords: Skeletal Muscle Fibers

1 The contractile properties and ATPase activity of skinned human skeletal muscle fibres from vastus lateralis were examined. Fibre types resolved single fibre segments by SDS-polyacrylamide gel electrophoresis. was determined enzymatic coupling ATP resynthesis to the oxidation NADH. 2 partitioning into (a) calcium-activated due actomyosin (AM) interaction, (b) sarcoplasmic reticular (SR) calcium pump, (c) basal (calcium independent) investigated comparing utilization before after exposure preparations for 30 min a solution containing 0.5 % Triton X-100, which effectively abolished SR activity. 3 Partitioning also measuring force at different concentrations butanedione monoxime (BDM), inhibits AM interaction. 4 results obtained with X-100 BDM similar. At saturating Ca2+ 20 °C, AM, activities per litre cell volume (±s.e.m.) amounted 46 ± 4, 51 19 μm s−1 in type I (n = 21), 139 14, 69 8 IIA 25), 137 22, 175 28 26 IIA/B 4) 108 13, 169 42 32 IIB 2). 5 These indicate that pumping fast is considerably larger than slow fibres. represents considerable fraction total (AM + basal)