CONTENTS XV 



VI. Hemoglobin 207 



1 Introduction 207 



1.1 Definition of Hemoglobin 207 



1.2 Nomenclature 208 



i Preparation and Properties 211 



2.1 Preparation 21 1 



2.1.1 Oxyhemoglobin 211 



2.1.2 Myohemoglobin 213 



2.1.3 Criteria for Purity 213 



2.2 Properties of Ferrous Compounds 214 



2.2.1 Oxyhemoglobin (Hb02) 214 



2.2.2 Hemoglobin (Reduced Hemoglobin, Ferrohemo- 

 globin, Hb), 215 



2.2.3 Carboxyhemoglobin (Carbon Monoxide Hemo- 

 globin, ' HbCO) 215 



2.2.4 Nitric Oxide Hemoglobin (HbNO) 216 



2.2.5 Cyanhemoglobin 216 



2.2.6 Carbylamine Hemoglobin (HbCHsNC) 217 



2.2.7 Nitrosobenzene Hemoglobin 217 



2.3 Properties of Ferric Compounds 218 



2.3.1 Henifglobin (Methemoglobin, Ferrihemoglobin, Hi) 218 



2.3.2 Hemiglobin Hydroxide (Alkaline Methemoglobin, 

 HiOH) 218 



2.3.3 Hemiglobin Fluoride (HiF) 219 



2.3.4 Hem/globin Cyanide (Cyanmethemoglobin, Ferri- 

 hemoglobin Cyanide) 219 



2.3.5 Hem/globin Azide 221 



2.3.6 Nitric Oxide Hem.iglobin 221 



2.3.7 Hem/globin Hydrosulfide 221 



2.3.8 Hydrogen Peroxide Hemiglobin 221 



2.3.9 Compounds with Cyanate and Thiocyanate 222 



2.3.10 Other Hem/globin Compounds 222 



2.4 Denatured Globin Hemochrome and Other Protein Hemo- 

 chromes 222 



2.4.1 Denatured Globin Hemochrome 222 



2.4.2 Denatured Globin Hemi'chrome (Kathemoglobin) . 223 



2.4.3 "Acid Hematin" 223 



2.4.4 Hemochrome Formation from Myohemoglobin .... 224 



2.4.5 Protein Hemochromes Occurring in Nature 225 



2.5 Summary of Spectroscopic Properties 225 



3 Linkage of Protein to Prosthetic Group 230 



3.1 Introduction 230 



3.2 The Linkage of Heme Iron to Globin 231 



3.2.1 Magnetochemical Evidence 231 



3.2.2 Evidence That Heme Iron Combines with Imid- 

 azoles 232 



3.2.2.1 Origin of the Imidazole Hypothesis 232 



3.2.2.2 Present Status of the Imidazole Hypoth- 

 esis 233 



3.2.2.3 Linkage in Hemiglobin 236 



3.2.2.4 Objections to the Imidazole Hypothesis 238 



