NADPH

**Info:** Nicotinamide adenine dinucleotide phosphate is a significant coenzyme of enzymatically catalyzed reactions involving oxidative reduction processes. It consists of nicotinamide, ᴅ-ribose and adenosine, to which a phosphate group is attached. It exists in two forms: reduced (NADPH) and oxidized (NADP⁺). The reduced form is oxidized by reversibly bringing together two protons and two electrons to the pyridine ring of nicotinamide.

**Photosynthesis function:** In the primary phase of the photosynthesis, reduction occurs first to produce NADPH (NADP⁺ + H⁺ + 2e⁻ → NADPH). In the secondary phase of the photosynthesis (in the Calvin cycle), the resulting NADPH molecules serve as a reducing agent. They oxidize themselves, and reduce the biosynthetic reaction substrates.