Skip to main content

Table 5 Inhibitor effects (I50 values) on AMPD from skeletal muscle of control versus frozen wood frogs

From: Regulation of 5'-adenosine monophosphate deaminase in the freeze tolerant wood frog, Rana sylvatica

  Control Frozen
  Free AMPD Bound AMPD Free AMPD Bound AMPD
Mg·GTP, mM 0.15 ± 0.02 0.08 ± 0.01 0.08 ± 0.01 a 0.10 ± 0.01
IMP, mM NE NE NE 0.23 ± 0.02 a
KCl, mM 660 ± 44 148 ± 34 702 ± 21 a 162 ± 24
NaCl, mM 973 ± 20 141 ± 31 824 ± 26 a 133 ± 21
NH4Cl, mM 276 ± 5.0 ND 254 ± 10 ND
  1. Data are means ± SEM, for determinations on Sephadex G50-filtered muscle extracts from n = 4 individual frogs. I50 is the inhibitor concentration that reduces enzyme velocity by 50%. a – Significantly different from the corresponding value for muscle from control frogs as assessed by the Student's t-test, P < 0.05. NE, no effect. ND, not determined. I50 values were measured at an AMP concentration of 0.5 mM.