Abstract
Crude extracts obtained by water extraction from the muscle of an ascidian (Halocynthia rotezi) are shown to possess an inhibitory activity on ATPase [(Na, K) ATPase, TF1-ATPase, HMM-ATPase]. Gel filtration of the extract with Sephadex G-10 separated the activity into two peaks, and the latter peak (inhibitor Ⅱ) was further purified by HPLC. This inhibitor was non-competitive for ATP and associated firmly with the (Na, K) ATPase.
