Table 1.

Comparison of mammalian myosin isoforms and Drosophila myosin properties

Myosin	D.R. of a head	<# of heads per filament>	Effective filament D.R.*	Actin-activated ATPase activity of a head (s−1)
myosin-IIA	~0.1a	58e	0.95	0.17a
myosin-IIB	~0.4b	60e	0.99	0.13b
myosin-IIC	~0.26c	28e	0.98	0.23c
Drosophila myosin-II	~0.1d	28f	0.81	0.54d

^a(Kovacs et al., 2003)

^b(Wang et al., 2003)

^c(Heissler and Manstein, 2011)

^d(Heissler et al., 2015)

^e(Billington et al., 2013)

^fper-communication with S. Heissler, N. Billington, and J. Sellers

^*effective filament D.R. = p(myosin filament is attached to F-actin), at any given time

effective filament $D.R.=1-{(1-D.R.)}^{\frac{n}{2}}$

D.R. = duty ratio

n = total number of heads per myosin mini-filament