The 105,000 x g supernatant fluid (S[subscript HS]) from extracts of pea seedlings
(Pisum sativum, var. Alaska) etiolated for 60 hours yielded a
very potent adenosine triphosphatase activity. This activity was designated
as an apyrase when the reaction stoichiometry indicated that
adenosine triphosphate (ATP) was hydrolyzed to adenosine monophosphate
(AMP)...