Physicochemical properties of selected porphyrin-based pigments^{12,16,17,19–21}.

Pigmenta	Molecular formula	Molecular weight (g mol−1)	UV-vis absorption maxima (nm)		Color in solution
			Soret	Q-bands
Heme	C34H32FeN4O4	616.5	416b	520, 550b	Red
Hemin	C34H34ClFeN4O4	654.0	363, 385c	550, 570c	Olive-green
Hematin	C34H34FeN4O5	634.5	364, 383c	613c	Dark blue-brown
Biliverdin	C33H34N4O6	582.7	376c	671c	Blue-green
Bilirubin	C33H36N4O6	584.7	452c	—	Yellow-orange
Protoporphyrin IX	C34H34N4O4	562.7	400d	506, 532, 580, 630d	Red-brown
Chlorophyll a	C55H72MgN4O5	893.5	430e	662e	Yellow-green
Chlorophyll b	C55H70MgN4O6	907.5	453e	642e	Blue-green
Chlorophyll c1	C35H30MgN4O5	611.0	444e	577, 626e	Blue-green
Chlorophyll c2	C35H28MgN4O5	609.0	447e	580, 627e	Blue-green
Chlorophyll c3	C36H28MgN4O6	637.0	452e	585, 627e	Blue-green
Bacteriochlorophyll a	C55H74MgN4O6	911.5	388	805, 870	Blue-green

^aFor structures, see Fig. 2, 3, 6, and 7.

^bMeasured in extracts of mitochondrial cytochrome c from a horse's heart.

^cMeasured in 1 M phosphate-buffered saline (PBS) containing 30 mM NaOH (hemin), 7.2 mM KOH (bilirubin) or 5 mM KOH (biliverdin).

^dMeasured in a mixture of acetonitrile and DMSO (3 : 1, v/v).

^eMeasured in diethyl ether.