IDENTIFICATION AND CHARACTERIZATION OF ATPASE ACTIVITY ASSOCIATED WITH MAIZE (ZEA-MAYS) ANNEXINS

An ATPase activity is associated with maize (Zea mays) annexins. It ha s a pH optimum of 6.0, shows Michaelis-Menten kinetics and is not stim ulated by Ca2+, Mg2+, EDTA or KCl; it is not inhibited by vanadate, mo lybdate, nitrate or azide, but N-ethylmaleimide inhibits by similar to 30% at 1-2 mM. These properties indicate that the activity is unlike other ATPases, although it has many features in common with the myosin ATPase. Gel filtration shows that the ATPase activity is mainly assoc iated with a 68 kDa protein that is extracted with the p33/p35 annexin s and cross-reacts with antibodies to these proteins.