What is porphyrin.
Types of porphyrin.
Structure of porphyrins.
Chemistry of porphyrins.
Porphyrin are colored and fluorosence.
Staniend glass art.
Biomedical importance.
Reference.
Porphyrins: Structure, Types, Properties and Biomedical Importance
1. By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )
2. What is porphyrin.
Types of porphyrin.
Structure of porphyrins.
Chemistry of porphyrins.
Porphyrin are colored and fluorosence.
Staniend glass art.
Biomedical importance.
Reference.
Introduction
3. Porphrin are a group of
organic compounds
Of which many occur in
nature in which various
side chain are
substituted for the eight
hydrogen atoms
numberd in the porphin
nucleus .one of the best
known is heme .the
pigment in red blood
cells
The name of porphyrin
coms from a greek word
for purpule
porphyrin
4. A porphyrin with a completely symmetric arrangement of
the substituents is classified as atype I porphyrin Only
types I and III are found in nature, and the type III series
is far more abundant and more important because it
includes heme.Heme and its immediate precursor,
protoporphyrin are both type III porphyrins (ie, themethyl
groups are asymmetrically distributed, as in type III
coproporphyrin)
they are sometimes identified as belonging to series IX,
because they were designated ninth in a series of
isomers postulated by Hans Fischer, the pioneer worker
in the field of porphyrin chemistry.
7. Porphins are planar molecules which contain large rings made by
joining four pyrrole rings with methine bridges. In the chlorins,
found in the chlorophylls, one of the rings (ring D in chlorophyllis
reduced. The specific class of porphins known as porphyrins
have eight substituents around the periphery of the largering. Like
the chlorins and the corrins of vitamin B12 (Section B), the
porphyrins are all formed biosynthetically from porphobilinogen.
This compound ispolymerized in two ways to give porphyrins
of types I and III .
Types of porphyrin
8. Most biologically important porphyrins belong to type III, in which
the first three rings A, B, and C have the same sequence of
carboxymethyl and carboxyethyl side chains, but in which ring D
has been incorporated in a reverse fashion. Thus, the
carboxyethyl side chains of rings C and Dare adjacent to each
other or phyrinscontaining all four carboxymethyl and four
carboxyethyl side chains intact are known as uroporphyrins.
Uroporphyrins I and III are both excreted in small amounts in the
urine. Another excretion product is coproporphyrin III, in which
all of the carboxymethyl side chains have been decarboxylated to
methyl groups The feathers of the tropical touraco are colored
with copper(II) complex of coproporphyrin III and this porphyrin as
well as others are commonly found in birds’ eggs. The heme
proteins are all derived from protoporphyrin IX, which is formed by
decarboxylationand dehydrogenation of two of the carboxyethyl
sidechains of uroporphyrin III to vinyl groups
.
9. The molecule found in plants
is chlorophyll, which is
responsible for the green
pigment normally seen in
leaves
Hemoglobin has a
structure in which the
porphyrin part called
heme is connected to a
big protein
10. . The left side half of the
corrin structure was
made by Woodward in
the United States, and
the right side half was
done by Eschenmoser in
Switzerland.
vitamin B12 is exceptionally complicated
12. A porphyrin is a rigid, square-planar molecule made
of four pyrroles (a five-membered ring containing a
nitrogen atom) connecting to form a larger ring. The
molecule is stabilized by the aromatic character
which extends over its entire structure.
13. The nitrogen atoms of a porphyrin occupy the four
sites on the square plane of an octahedron, leaving
two empty sites on the top and the bottom Figure
These two sites are then filled by the axial ligands,
which are known to react in special ways. By using
them, biological systems carry out a wide range of
chemical reactions
15. A Utility Player
This molecule called porphyrin, is one of those
compounds with unique characteristics that are utilized
cleverly at important point
16. PORPHYRINS ARE COLORED&
FLUORESCE
The various porphyrinogens are colorless,
whereas the various porphyrins are all colored.
In the study of porphyrins or porphyrin
derivatives, the characteristic
absorptionspectrum that each exhibits—in both
the visible and the ultraviolet regions of the
spectrum—is of great value.
An example is the absorption curve for a
solution of porphyrin in 5% hydrochloric acid
Note particularly the sharp absorption band near
400 nm. This is a distinguishing feature of the
porphin ring and is characteristic of all
porphyrins regardless of the side chains present.
17. This band is termed the Soret band after its
discoverer, the French physicist Charles Soret.
When porphyrins dissolved in strong mineral acids
or in organic solvents are illuminated by ultraviolet
light, they emit a strong red fluorescence.
This fluorescence is so characteristic that it is often
used to detect small amounts of free porphyrins.
The double bonds joining the pyrrole rings in the
porphyrins are responsible for the characteristic
absorption and fluorescence of these compounds;
these double bonds are absent in the
porphyrinogens.
18. A characteristic property of the porphyrins is the
formation of complexes with metal ions bound to the
nitrogen atom of the pyrrole rings
Examples are the iron porphyrins such as heme of
hemoglobinand the magnesium-containing
porphyrinchlorophyll, the photosynthetic pigment of
plants.
Proteins that contain heme (hemoproteins) are widely
distributed in nature
19. Porphyrins are the conjugate acids of ligands that
bind metals to form complexes. The metal
ionusually has a charge of 2+ or 3+. A schematic
equation for these syntheses is shown:
H2porphyrin + [MLn]2+ → M(porphyrinate)Ln-4 +
4 L + 2 H+
A porphyrin without metal in its cavity is a free
base. Some iron-containing porphyrins are called
hemes. Heme-containing proteins, or
hemoproteins, are found extensively in nature.
Hemoglobin and myoglobin are two O2-binding
proteins that contain iron porphyrins.
20. Several other heterocycles are related to
porphyrins. These include corrins, chlorins,
bacteriochlorophylls, and corphins. Chlorins
(2,3-dihydroporphyrin) are more reduced,
contain more hydrogen than porphyrins, and
feature a pyrroline subunit. This structure
occurs in chlorophyll. Replacement of two of the
four pyrrolic subunits with pyrrolinic subunits
results in either a bacteriochlorin (as found in
some photosynthetic bacteria) or an
isobacteriochlorin, depending on the relative
positions of the reduced rings
21. A number of porphyrin derivatives are
continuously made, and among them the
compounds composed of multiple porphyrin
units are particularly fascinating. Putting difficult
lectures aside, let’s enjoy looking at some of the
structures as beautiful as stained-glass art
cyclic porphyrin pentamer
24. BIOMEDICAL IMPORTANCE
*The biochemistry of the porphyrins and of the bile pigments is
presented these topics are closely related, because heme is
synthesized from porphyrinsand iron, and the products of
degradation ofheme are the bile pigments and iron.
* the porphyrins and heme is basic to understanding the varied
functions of hemoproteins in the body
* porphyrins are cyclic compounds formed by the linkage of
four pyrrole rings through HC methenyl bridges .
*An interesting application of the photodynamic properties of
porphyrins is their possible use in thetreatment of certain
types of cancer, a procedure called cancer phototherapy.
25. References
*Harper,’s biochemistry 26 edition
By Robert k murray, Daryl k granner ,Peter a mayes,
Victor w rodwell
Medcal publishing divison
*Biochemistry the chemicalreaction ofliving cells 2 edition
By David e metzler
*Lehninger principles of biochemtry 4 edition
By D l nelson, Michael m cox
* www.google.com
* www.wikipedia.com
* wwwkbiotec.com