Figure 2

Specific activities of the (A) NADP⁺-specific forward reaction in which NADPH was added as co-factor, (B) NADP⁺-specific reverse reaction in which NADP⁺ was utilised as co-factor, (C) NAD⁺-specific forward reaction with NADH as co-factor and (D) NAD⁺-specific reverse reaction in which NAD⁺ was utilised as co-factor. Each enzyme reaction was assayed under conditions of nitrogen limitation (3 mM (NH₄)₂SO₄) and in response to an ammonium pulse (60 mM (NH₄)₂SO₄). One unit of enzyme activity was defined as the oxidation/reduction of 1 nmole co-factor per minute per milligram ofprotein. The mean specific activity with standard deviations is included.