煙酰胺腺嘌呤二核苷酸磷酸(nicotinamide adenine dinucleotide phosphate)縮寫NADP，曾稱為三磷酸吡啶核苷酸（TPN）或輔脫氫酶Ⅱ或輔酶Ⅱ。它是一種輔酶，是煙酸酰胺腺嘌呤二核苷酸與一個磷酸分子以酯鍵結合的物質，廣泛存在生物界。化學性質、吸收光譜、氧化還原形式等均類似NAD。它通過6-磷酸葡萄糖脫氫酶（EC．1．1．1．49），6-磷酸葡萄糖酸脫氫酶（EC．1．1．1．44）等，可被許多脫氫酶進行可逆的還原。但是與很多利用NAD的脫氫酶不一定能進行反應，也不能呼吸鏈直接氧化。在好氧生物的細胞中與NAD不同，它主要以還原態存在。氧化型輔酶Ⅱ二鈉（NADP,disodium salt）用作各種診斷檢測中的輔助因子。 

Formula: C₂₁H₂₆N₇O₁₇P₃Na₂
Molecular weight: 787.4 D (NADP: 743.4 D)
Appearance: White to yellowish amorphous powder
Solubility: Clear, colorless solution in water (c=50 mg/ml)
NADP, Na-salt (from value found enzymatically, based on dry weight): ≥97%
NADP (enzymatically, A₃₄₀, ε=6.3 [l x mmol^-1 x cm^-1]): ≥85%
NADP (A₂₆₀, ε=18 [l x mmol^-1 x cm^-1]): ≥85%
Na (flame photometric): 4.5±0.5%
Water (K. Fischer): ≤6%
NAD (enzymatically): ≤0.5%
Methanol (GC): ≤3%
A₃₆₀ (c=10 mg/ml water, against water): ≤0.600
A₃₄₀ (c=0.01 mg/ml phosphate buffer, pH 7.0): ≤0.005
Stability: At +2 to +8°C within specification range for 24 months.Store dry.