STINE, G. J. 1969. Enzyme activities during the asexual cycle of Neurospora crassa. 111. Nicotinamide adenosine diphosphate glycohydrolase. Can. J. Microbial. 15: 1249-1254. The level and specific activity of nicotinamide adenosine diphosphate glycohydrolase (NADase) were followed throughout the asexual cycle in Nelrrospora crassa. A large quantity of NADase associated with the conidia was water soluble. NADase activity rapidly disappeared from the growth medium during conidial germination and from early logarithmic mycelial growth. As the mycelia aged, the enzyme accumulated in the growth medium and in the aging aconidial conidiophores, regardless of their inability to produce conidia. Since the enzyme was synthesized as the culture aged, it appears that the conidiophores age quickly with respect to their production of NADase. Conidia produced from conidiophores of the wild-type culture contained about the same quantity of NADase as the inoculum conidia. The accumulation of NADase in the conidia of wild-type Neurospora is due to the normal differentiation of these conidia in the absence of a liquid environment. The enzyme becomes locked into the conidia being differcntiated from conidiophores that contain large amounts of the NADase activity.