CONTENTS xni 



2.3 Relation of Color and Light Absorption to Structure 107 



2.4 Gmelin Reaction and Oxidation Products of Bilatrienes. ... 109 

 Bilatrienes. Verdins ^ ^^ 



3.1 Structure ^ ^^ 



3.2 Individual Bilatrienes ^^^ 



3.2.1 Bilatriene, Biliverdin ■ 1 14 



3.2.2 Mesohilatriene, Mesobiliverdin ("Glaucobilin") ■ ■ 115 



3.2.3 Other Bilatrienes 116 



3.3 Reactions and Properties 1 16 



Biladienes-(a,c). Rubins H^ 



4.1 Structure 11^ 



4.2 Individual Biladienes-(a,c) 120 



4.2.1 Bilirubin 120 



4.2.2 Mesobilirubin 120 



4.3 Color Reactions 121 



4.4 Absorption Spectra and Metal Complexes 121 



4.5 Surface Properties and Adsorption 123 



Biladienes-(a,b) and Related Substances 123 



5.1 Biliviolinoid Sul)stances 123 



5.2 Mesobiliviolin (Mesobiliviolin Type 1, Lemberg) 125 



5.2.1 Structure 125 



5.2.2 Absorption Spectra and Complex Salts 126 



5.2.3 Occurrence of Mesobiliviolin in Nature 127 



5.3 Mesobilierythrin (I^mberg), Mesobilirhodin (Siedel), and 

 Phycoerythrobilin 128 



5.4 Bilipurpurins IBiladiene-(a,b)-ones-(c)] and Related Sub- 

 stances '""" 



5.4.1 Structure 130 



5.4.2 Properties 1^1 



5.4.3 Bilichrysins 133 



5.4.4 Bilierythrinoid Oxidation Products of Bilatrienes . . 133 



Bilanes, Bilenes, and Related Substances • 134 



6.1 Occurrence of Mesobilane and Tetrahydromesobilane and 



the Corresponding Bilenes in Feces and Urine 134 



6.2 Mesobilane and Mesobilenes 136 



6.2.1 Structure 136 



6.2.2 Properties of Mesobilane and Mesobilene-(b) 138 



6.3 Tetrahydromesobilane (Stercobilinogen, Urobilinogen B), 



and Tetrahydromesobilene-(b) (Stercobilin) HO 



6.3.1 Structure l^^ 



6.3.2 Properties 141 



6.4 (/-Urobilin 1*3 



6.5 Porphobilin 1'** 



6.6 Bilenediones and Bilenetetrols (Choletelins) 144 



Bile Pigment Chromoproteins 145 



7.1 Chromoproteins of Red and Blue Algage 145 



7.2 Bile Pigment Chromoproteins in Animals 148 



Dipyrrolic and Related Pigments Occurring in Nature 149 



8.1 "Bilifuscins" (a,a'-Dihydroxypyrromethenes) 149 



8.2 Pentdyopent 1^^ 



8.3 Porphobilinogen 151 



8.4 Bacterial Pigments 152 



