Table 1 |.

Properties of genetically encoded redox sensors.

	Sensor	Species sensed	Dynamic changes(%)	Kd or Midpoint Potential	Fluorescent protein	Detection mode	Sensor type	pH sensitivity
NADPH/NADP+	iNap18	NADPH	900	~2 μM;	cpYFP	Fluorescence intensity	Ratiometric	Resistanta
	iNap28		1000	~6.4 μM;
	iNap38		900	~25 μM;
	iNap48		500	~120 μM;
	Apollo-NADP+38	NADP+	15–20	0.1–20 μM	FP	Fluorescence anisotropy	Ratiometric	Resistant
NADH/NAD+	Frex24	NADH	800	~3.7 μM;	cpYFP	Fluorescence intensity	Ratiometric	Sensitive
				~11 μMb
	LigA-cpVenus37	NAD+	100	~65 μM	cpVenus	Fluorescence intensity	Ratiometric	Sensitive
	SoNar22,23	NADH/NAD+ ratio	1500	~40	cpYFP	Fluorescence intensity	Ratiometric	Resistanta
	Peredox27	NADH/NAD+ ratio	150	~330	cpT-Sapphire	Fluorescence intensity	Intensiometric	Resistant
	RexYFP28	NADH/NAD+ ratio	50	N.D.	cpYFP	Fluorescence intensity	Intensiometric	Sensitive
-SH/-SS-	roGFP114,15	-SH/-SS-	350	−288 mV	GFP	Fluorescence intensity	Ratiometric	Resistant
	roGFP214,15		480	−272mV				Sensitive
	roGFP-iX53		140–620	−229 to −246 mV				Sensitive
	rxRFP17,43	-SH/-SS-	400	−290 mV	cpmApple	Fluorescence intensity	Intensiometric	Sensitive
	rxYFP54	-SH/-SS-	300	−261 mV	YFP	Fluorescence intensity	Intensiometric	Sensitive
	Grx1-roGFP216	GSSG/GSH	800	−280 mV	roGFP2	Fluorescence intensity	Ratiometric	Resistant
H2O2	HyPer18	H2O2	200	−185 mV	cpYFP	Fluorescence intensity	Ratiometric	Sensitive
	HyPer255		500	N.D.
	HyPer356		450	N.D.
	HyPerRed19	H2O2	80	N.D.	cpmApple	Fluorescence intensity	Intensiometric	Sensitive
	roGFP2-Orp120	H2O2	410–510	N.D.	roGFP2	Fluorescence intensity	Ratiometric	Resistant
	roGFP2-Tsa2ΔCR21	H2O2	500	N.D.	roGFP2	Fluorescence intensity	Ratiometric	Resistant

N.D., not determined. FP, Fluorescent protein

^aiNap’s or SoNar’s fluorescence excited at 420 nm, dynamic range, and K_d are pH resistant.

^bThe apparent NADH dissociation constant (K_d) of Frex was ~3.7 μM at pH 7.4 and ~11 μM at pH 8.0, respectively.