IRON PORPHYRINS, VOL. 4

Porphyrins play a vital role in many biological functions including oxygen transport, electron transfer and catalyzing the incorporation of oxygen into other molecules.

This current survey discusses the use of modern physical techniques to probe porphyrin structure and function. The authors review the data available through a particular technique and show what can be learned therefrom about the (electronic) structure and function of biologically important porphyrins. The techniques include magnetic circular dichroism, X-ray absorption fine structure (EXAFS) and M?ssbauer spectroscopies. All contributors are well known in their respective fields, enjoying world-wide reputation.

1. Magnetic Circular Dichroism Spectroscopy of Iron Porphyrins and Heme Proteins

John H. Dawson and David M. Dooly

A. Introduction

B. Simple Heme Proteins and Model Iron Heme Complexes

i. Hemoglobin and Myoglobin

ii. Leghemoglobin

iii. Tryptophan and Indoleamine Dioxygenases

iv. Cytochrome b and Hemopexin

v. Peroxidases

vi. Catalase

vii. Cytochromes c and f

viii. Cytochrome P-450

ix. Chloroperoxidase

x. Additional Iron Heme Model Complexes

C. Multiheme-Containing Enzymes

i. Mammalian Cytochrome c Oxidase

ii. Pseudomonas Cytochrome Oxidase (Cytochrome cd, Nitrite Reductase)

Acknowledgments

Notes

References

Addendum to Chapter 1: Recent Advances in the Magnetic Circular Dichroism Spectroscopy of Iron Porphyrins and Heme Proteins

John H. Dawson and David M. Dooley

A. Introduction

B. Simple (Noninteracting) Heme Proteins and Model Iron Porphyrin Complexes

i. Hemoglobin, Myoglobin, and Leghemoglobin

ii. Indoleamine Dioxygenase, Prostaglandin H Synthase, and Cytochrome c?

iii. Cytochromes b_5, b_562, c, c_3, and c_551

iv. Formate Dehydrogenase and Nitrate Reductase

v. Peroxidases

vi. Cytochrome P-450 and Chloroperoxidase

vii. Yeast Complex III

viii. Additional Heme Proteins and Models

C. Multiheme Enzymes

i. Introduction

ii. Mammalian Cytochrome c Oxidase

iii. Pseudomonas aeruginosa Cytochrome Oxidase (Cytochrome cd, Nitrite Reductase)

iv. Pseudomonas aeruginosa Cytochrome c-551 Peroxidase

v. Wolinella succinogenes Nitrite Reductase

Acknowledgments

References

2. M?ssbauer Spectroscopy of Iron Porphyrins

P. G. Debrunner

A. Introduction

B. Formalism

C. Experimental Considerations

D. Low-Spin Ferric Complexes, S = 1/2

E. Ferric High Spin, S = 5/2

F. Ferric Intermediate Spin, S = 3/2

G. Ferrous Low Spin, S = 0

i. PFeLL'

ii. PFeLCO

iii. PFeLO_2

H. Ferrous High Spin, S = 2

I. Ferrous Intermediate Spin, S = 1

J. Ferryl Porphyrins and Other Higher Oxidation States

K. Miscellaneous Cases

i. Hemoglobin NO

ii. Spin Transitions

iii. Porphyrin Dimers

iv. Spin-Coupled Systems

L. Iron Phthalocyanine

M. Iron Porphyrin Literature to Mid 1987

Notes

References

3. X-Ray Absorption Spectroscopy of Iron Porphyrins

James E. Penner-Hahn and Keith O. Hodgson

A. Introduction

B. Physical Principles of X-Ray Absorption

i. X-Ray Absorption Edge Structure

ii. EXAFS

iii. Strengths and limitations

C. Experimental Considerations

i. Sample Requirements

ii. Equipment and Data Collection Requirements

iii. Potential Problems

D. X-Ray Absorption Data Analysis

i. Data Reduction

ii. Techniques of Data Analysis

iii. Sources of Error

E. Applications of X-Ray Absorption Spectroscopy to Porphyrins

i. Model Compounds, EXAFS

ii. Model Compounds, XANES

iii. Hemoglobin and Myoglobin

iv. Electron Transfer Hemoproteins

v. Cytochrome P-450 and Chloroperoxidase

vi. Horseradish Peroxidase

vii. Cytochrome-c Oxidase

F. Future Developments and Applications

Acknowledgments

References

Index