3.4.22.43 additional information - rapid loss of activity at neutral pH 3.4.22.43 4.5 5.5 very stable 3.4.22.43 5.5 - 2 h stable 3.4.22.43 5.5 - 37°C, loss of 60% activity within 20 min 3.4.22.43 6.5 - 2 h, residual acitviy 3.4.22.43 7 - 1 h, residual acitviy