Books
in black and white
Main menu
Share a book About us Home
Books
Biology Business Chemistry Computers Culture Economics Fiction Games Guide History Management Mathematical Medicine Mental Fitnes Physics Psychology Scince Sport Technics
Ads

The porphyrin handbook - Kadish K.M.

Kadish K.M. The porphyrin handbook - Academic press, 2000. - 368 p.
Download (direct link): kadishsmishgulilard2000.djvu
Previous << 1 .. 181 182 183 184 185 186 < 187 > 188 189 190 191 192 193 .. 240 >> Next

.... 310
K. Kinetic Aspects of
Recognition..............................................................
.................... 311
III. Electron Transfer Regulated by Molecular
Recognition............................................................
312
A.
Introduction.............................................................
....................................... 312
B. Design of Donor-Acceptor Pairing via Noncovalent
Interaction.................................................... 312
C. Determination of ET Rate
Constants................................................................
.............. 313
D. Noncovalently Linked Donor-Acceptor Pairings via Hydrogen-Bonding
Interaction................................... 313
1. Convergently Linked Donor-Acceptor Pairings Formed by Hydrogen
Bonding...................................... 313
2. Divergently Linked Donor-Acceptor Pairings Formed by Hydrogen
Bonding....................................... 314
E. Noncovalently Linked Donor-Acceptor Pairings via van der Waals
Contacts......................................... 317
The Porphyrin Handbook
K.M. Kadish, K,M. Smith, R. Guilard, Eds,
Volume 6 / Applications: Past, Present and Future
Copyright (c) 2000 by Academic Press 279 All rights of
reproduction in any form reserved.
ISBN 0-12-393200-9/530,00
280
Ogoshi et al.
F. Noncovalently Linked Donor-Acceptor Pairings via Metal
Coordination............................................ 318
G. Energy Transfer Within Noncovalently Linked Donor-Acceptor
Complex............................................. 320
H. Intracomplex ET via Molecular-Recognition Process on Protein
Surface........................................... 322
1. Cytochrome Binding
Porphyrins...............................................................
................ 322
2. Interprotein ET Models Formed by Chemical Modification of
Myoglobin........................................... 323
I. Survey of ET Model
Systems..................................................................
................... 325
(V. Self-Organized porphyrin
Systems..................................................................
.................. 325
A. Covalently Linked Multiporphyrin
Systems..................................................................
..... 326
B. Self-Assembling Multiporphyrin
System...................................................................
....... 328

References...............................................................
........................................ 336
I. New Aspects of Synthesis and Design
of Porphyrins for Receptor Models
A. INTRODUCTION
A century ago, Emil Fischer presented the "key and lock" concept to
enable understanding of complementary interactions within the enzyme-
substrate complex at binding sites in the enzymatic reactions. Half a
century later, Pauling and Haldane emphasized the importance of
complementary interactions between substrates and enzymes at the
transition state rather than the ground state. The idea of catalytic
antibodies was derived from the concept of a transition-state
approximation of the enzyme substrate by mutagenetic techniques.
Furthermore, modern host-guest chemistry seems to help in the
understanding of biological molecular recognition by receptor proteins of
various types of organic compounds, hormones and pheromones acting as
molecular signals. The concept of "preorganization" introduced by Cram in
the host-guest chemistry field is intended to design the host compound so
that it gives rise to a complementary interaction with a guest molecule
via noncovalent bonding.
Syntheses of porphyrins and metalloporphyrins have been widely
investigated over the last three decades to provide models which mimic
functions of heme proteins, heme enzymes and supramolecular assembly of
chlorophyll in green plants and photosynthesis bacteria. Results on the
syntheses and structure of biomimetic porphyrins up to 1985 have been
reviewed by Morgan and Dolphin.1
Stereo- and regio-specific syntheses of the precursor pyrrole
derivatives and porphyrins have been developed to clarify the mechanism
of biosynthesis of cyclic tetrapyrroles such as protoheme, chlorophylls,
and vitamin B12. In addition to this biologically important pyrrole
chemistry, synthetic strategies of multifunctional porphyrins and
metalloporphyrins have been extended to enable their use as building
blocks and highly sensitive probes for elucidation of the reversible
processes of molecular recognition relevant to naturally occurring small
organic substrates such as amino acids, saccharides, nucleotides,
hormones and pheromones. The most prominent features of the porphyrin
framework can be summarized as follows:
Previous << 1 .. 181 182 183 184 185 186 < 187 > 188 189 190 191 192 193 .. 240 >> Next