TABLE 4.

Activities of isocitrate lyase and 2-methylisocitrate lyase in cell extracts of S. cerevisiae CEN.PK113-7D in steady-state chemostat cultures^a

Carbon source	Nitrogen source	Activity (μmol · min−1 · mg of protein−1) of:		me-ICL/ICL
		ICL	me-ICL
Ethanol	Ammonia	0.15 ± 0.02	0.09 ± 0.00	0.63
Glucose	Ammonia	0.01 ± 0.00	0.03 ± 0.00	3
Glucose	Ammonia	<0.002	<0.002	NAb
Glucose (anaerobic)	Ammonia	<0.002	<0.002	NA
Glucose	Threonine	<0.002	0.10 ± 0.01	>50
Glucose	Threonine	<0.002	<0.002	NA

^aThe growth-limiting substrates are printed in bold. Unless otherwise indicated, cultures were aerobic (dissolved oxygen concentration above 60% of air saturation). Data are presented as the ± the standard deviations of two independent chemostat cultivations. D = 0.10 h⁻¹. 

^bNA, not applicable.