4.2.1.45 NAD+ - 4.2.1.45 NAD+ required 4.2.1.45 NAD+ catalytic prosthetic group, NAD+ serves as a hydride carrier receiving the 4H of the substrate in the oxidative half-reaction and passing the reducing equivalents to C-6 in the reductive half-reaction, the substrate is bound to the si-face of the nicotinamide ring 4.2.1.45 NAD+ two binding sites per enzyme molecule 4.2.1.45 NAD+ dependent 4.2.1.45 NADP+ 20% of the activity with NAD+