Biological role of metals

2. Biochemistry deals with biomolecules of life, usually
of organic in nature. Some biomolecules contain
metal ions or inorganic constituents.
Chlorophyll – Mg
Hemoglobin - Fe
The branch of chemistry that deals with the
study of inorganic constituents in biologial systems is
known as Bioinorganic Chemistry.
It act as a bridge between biochemistry and
inorganic chemistry and tries to explain the role of
inorganic constituents in biochemical process.

3.  It is the study of naturally occurring inorganic elements and metals in
living systems.
Metals are introduced as probes or drugs
Biochemistry
Inorganic
chemistry
Bio-
inorganic
chemistry

4. Bio-inorganic
chemistry
Microbiol
ogy
Environme
ntal
toxicology
Metals in
medicine
Bio-
coordinati
on
chemistry
Molecular
biology
Crystallog
raphy
Spectrosc
opy

5. Bio-molecules that contain one or more metallic elemen
ts can be referred as metallo-biomolecules.
Metal act as the active site and involves in different biochemical
reactions such as electron transport, transport of oxygen and c
atalysis etc.
Example: -
 Myoglobin
 Hemoglobin
 Ferritin
 Cytochromes
 Enzymes etc…………

7. Elements
Essential
element
H2, O2, C, N2, Ca,
P, Na…..
Trace elements
Mo, Mn, Zn,
Co, Cu…
Ultra trace
elements
Li, Si, V, Cr, W
Non-essential
As, Ni, Al, Pb
etc

8.  Cellular communication
 Na+ flux across a cell membrane triggers neutron firing.
 Ca2+ has influence on muscle activity.
 Regulation of gene expression (Zn2+)
 Nucleic acid interactions
 Iron transport and storage
 Metalloenymes

11. Arsenic commonly occurs in insecticides, fungicides and herbicides.
As (III) are the most toxic
⟹ Attack SH group of an enzyme thereby inhibiting enzyme action.
⟹ The inhibitory action is based on inactivation of pyruvic dehydrogenase by
omplexation with As (III).

13. ⟹ By virtue of the chemical similarity between P and As, it interferes with so
me biochemical processes involving P.
Example :-
Phosphorylation is replaced by arsenolysis ⟹ In the enzymatic synthesis of
ATP generation

14. The three major biochemical actions of arsenic are
o Coagulation of protein
o Complexation with co-enzymes
o Uncoupling of phosphorylation.

15. Arsenic

16. • The major portions of Cd enter into our body by ingestion or by inhalation
• At high levels, Cd causes kidney problems, anemia and bone marrow disor
ders.
• When excessive amounts of Cd2+ are ingested it replaces Zn2+ at key enzy
matic sites which leads to metabolic disorders.

17.  On inhalation Hg vapours enter the brain through blood via lunges
by diffusion and can cause server damage to central nervous system.
 Inorganic mercuric compounds mainly attack liver and kidney

18.  The toxicity depends on the chemical form and entrance route into the body.
Some important forms of mercury are;
Mercurous ion
(Hg2
2+)
•Forms insoluble
chloride ions
• Not toxic
Mercuric ion
(Hg2+)
• Fairly toxic
• High affinity
for sulphur
Organomercurials
Eg : - CH3Hg+
• Most toxic
•Soluble in fat
• Ability to move
through placental
barriers and enter
foctal tissues
•Cause irreversible
brain damage.

19. More than 100 people lost
their lives and many
thousands were permanently
paralyzed from having
mercury-contaminated fish.
The Hg was deposited on the
bottom of the Bay and
remained there.

20. Where 450 villagers died after eating wheat which had been dusted with
mercury- contain pesticide.

21. But it has lots of applications in various industries: -
 Chlor - alkali industry
 In the manufacture of Cl2 and NaOH
 Production of electrical apparatus like Hg vapour
lamp, electrical switches, Hg batteries etc.
 In agricultural industries
 Dressing

22. Biochemical effects of Mercury
• Bioaccumulation
• Affects CNS, Gastro-intestinal system and
renal.

23. • Causes Hunter-Russell syndrome and
Minamata disease