Fig. 5
From: Developmental myosins: expression patterns and functional significance
Kinetic properties of neonatal myosin. a, b Postnatal changes in maximum shortening velocity (a) and ATPase activity (b) in rat extensor digitorum longus (EDL) muscle. Note that the developmental replacement of neonatal myosin with adult fast myosin during the first week after birth is accompanied by a twofold increase in Vmax and ATPase activity. (Panel a redrawn from Table 1 of [91], panel b redrawn from Figure 3 (a) of [92]). c Unloaded shortening velocity of single fibers of rabbit psoas increases during postnatal stages concomitantly with the replacement of neonatal with adult fast isoforms (redrawn from data in text and in Figure 2 of [96]). d Myofibrillar ATPase activity of single fibers isolated from neonatal and adult rat diaphragm muscle and identified in relation to their MyHC isoform composition. Note the lower ATPase activity of neonatal compared to adult fast fibers (redrawn from data in Figure 4 of [98])