The Production of Ammonia by Multiheme Cytochromes c - The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment - page 207

Chapter 9
The Production of Ammonia by Multiheme
Cytochromes c

J ¨ rg Simon and Peter M.H. Kroneck

Contents
ABSTRACT ................................................................................... 211

1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

2 AMMONIA AND ITS ROLE IN THE ENVIRONMENT . . . . . . ........................ 214

3 ENZYMES INVOLVED IN AMMONIA TURNOVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

4 CYTOCHROME c NITRITE REDUCTASE AS PARADIGM ........................ 217

4.1 Cytochrome c Nitrite Reductase-Containing Organisms and Their Physiology . . 221

4.2 Biochemistry and Structure of Cytochrome c Nitrite Reductase .................. 221

4.3 Electron Transfer Routes to Cytochrome c Nitrite Reductase .................... 227

4.4 Role of Cytochrome c Nitrite Reductase in Stress Defense . . . . . . . . . . . . . . . . . . . . . . . 230

5 OTHER MULTIHEME CYTOCHROMES c ............................................ 231

6 ENVIRONMENTAL ISSUES AND CONCLUSIONS ................................. 231

ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

REFERENCES ................................................................................ 233

Abstract The global biogeochemical nitrogen cycle is essential for life on Earth.
Many of the underlying biotic reactions are catalyzed by a multitude of prokaryotic
and eukaryotic life forms whereas others are exclusively carried out by microor-
ganisms. The last century has seen the rise of a dramatic imbalance in the global
nitrogen cycle due to human behavior that was mainly caused by the invention of
the Haber-Bosch process. Its main product, ammonia, is a chemically reactive and