Influence of the carbon source on glycerol kinase activity in Neurospora crassa

The level of glycerol kinase activity in Neurospora crassa was shown to change in response to resuspension of sucrose-grown mycelia in fresh medium containing a new carbon source: the magnitude of the change depended on the new carbon source provided. Certain carbon sources, such as glucose and fructose, inhibited the small increase that occurred in the absence of any carbon source. Others, and in particular deoxyribose, galactose, glycerol and ribose, greatly enhanced this increase. The activity induced by deoxyribose and galactose had the same stability, both in vivo and in vitro, as that induced by glycerol, and as that induced by incubation of Neurospora cultures at low temperatures. The inhibitory carbon sources, such as glucose and fructose, also restricted the increases induced by deoxyribose, galactose and glycerol: they had more effect on the increases induced by glycerol and deoxyribose than on that induced by galactose. The increase in activity that occurs at low temperature was also inhibited by glucose and sucrose.