CONTENTS XXI 



4.2.2 Spectrophotometric Analysis 474 



4.3 Structure of the Prosthetic Group 474 



4.4 Mechanism of Choleglobin Formation 475 



4.4.1 Principle of the Mechanism 475 



4.4.2 Stroma Factor 477 



4.4.3 Green Pigment 478 



4.4.4 Various Hydrogen Donors Producing Choleglobin. 478 



4.4.5 The " Viridans" EfiFect 480 



5 "Easily Detachable Iron" and Nonhemoglobin Iron in Blood 482 



5.1 Easily Detachable Iron 482 



5.2 Nonhemoglobin Iron 484 



5.3 Differences between Carbon Monoxide Capacities before and 

 after Reduction 485 



6 Pseudohemoglobin and Cruoralbin 486 



6.1 Pseudohemoglobin 486 



6.2 Cruoralbin and Cruoratin 488 



6.3 Formation of Similar Green Hemoglobins without Cyanide. . 489 



6.4 Reaction Mechanism 489 



7 Sulfhemoglobin 490 



7.1 Historical 490 



7.2 Properties of Sulfhemoglobin 491 



7.3 Protein of Sulfhemoglobin 492 



7.4 "Sulfhemoglobin" as a Mixture of Sulfhemoglobin and 

 Choleglobin 492 



7.5 Sulfur Content of Sulfhemoglobin and Mode of Formation. . 493 



7.6 Reconversion of Sulfhemoglobin to Protoporphyrin Deriva- 

 tives and Nature of Its Prosthetic Group 495 



7.7 Myosulfhemoglot)in 497 



7.8 Distinction between Sulfhemoglobin and Compounds with 

 Similar Absorption Spectra 497 



8 Verdoheme and Choleheme Compounds in Hematin Enzymes 499 



8.1 Verdohemochrome Formed from Cytochrome c 499 



8.2 Bile Pigment Hematin in Liver Catalase 499 



9 Breakdown of Hemoglobin and Myohemoglobin to Dipyrrolic Com- 

 pounds 500 



XI. Hemoglobin Catabolism, I. Breakdown to Bile Pigments. . 503 



1 Introduction 503 



1.1 Formation of Bile Pigments from Hemoglobin 503 



1.2 Earlier Theories of the Mechanism 504 



1.3 Importance of Biliverdiii 505 



1.4 Modern Views on the Mechanism of Hemoglobin Breakdown 507 



2 Life Span of the Erythrocyte 508 



2.1 Introduction 508 



2.2 Life Span of the Cell Deduced from Pigment Metabolism. . . 509 



?.2.1 Bilirubin Excretion 509 



2.2.2 Urobilin Excretion 510 



2.2.3 Other Methods 510 



2.3 Life Span of the Cell Deduced from Histological and Immu- 

 nological Evidence 511 



2.4 Significance of tlie Mortality Curve 512 



