Details of bioinorganic elements , functions, structures discussed.

1. Bio inorganic Chemistry
Essential and trace elements in biological process,
metalporephyrins w.r.t. haemoglobin and chlorophyll
(structure and function), biological role of Na, K, Fe and
Zn.
PRESENTED BY:
Dr. Seema S. Pattanshetti
Assistant Professor of Chemistry
S.Nijalingappa Sugar Institute,
College of B.Sc. (Sugar Science &
Technology), Belagavi

2. Introduction:
• Inorganic reagents and reactions have played an important role in the
formation and development of organic life molecular on the earth from
very beginning of life on earth.
• Inorganic chemistry is involved in structure and functions of all life
forms present on earth.
• Bioinorganic chemistry :
• It is the inorganic chemistry of living organisms. It is concerned with
the functions of all metallic and most non-metallic elements in
biology.
• These metal ions play in a vast number of widely differing biological
processes.

3. Introduction:
• It stretches from chemical physics to clinical medicine.
• The bioinorganic chemistry is about structure, function, mechanism
and dynamics of biologically relevant metal complexes and metal
containing proteins.

4. HISTORY An Interdisciplinary Research Field
Bulk inorganic elements long been
known to be essential
Blood known to contain iron since
17th century
Need for Zinc, 1896
Bioinorganic chemistry developed
as a field after 1960
First inorganic biochemistry
symposium in 1970
SBIC (Society of Biological Inorganic
Chemistry) formed in 1995

5. Functions of Metals in Mammals
• Structure Hard material –bone and teeth
• Cell membranes
• DNA and RNA structure
• Protein, including enzyme conformation
• Charge carriers : Na+, K+, Ca2+
• Electron transfer (Redox reactions) : Fe, Cu, Mn, Mo, Ni, Co
• Metabolism : Degradation of organic molecules
• Activation of small molecules : O2, CO2

6. Bio Inorganic chemistry
• These bioinorganic materials mainly present on the earth. Atmosphere
contains Co2, N2, H2O as main components and trace amount of gases
like H2, CO. H2O, NH3 and CH4 from volcanic exhalations, cosmic
rays, radioactivity etc.
• Many inorganic elements plays an important role in physiological
content some are – Fe, Cu, Zn are present mainly in all organisms.
• Other elements are in traces. i.e. Hydrogen, Lithium, Sodium,
Manganese, Calcium, potassium Mn, Fe, Co, Ni, As, Br, Sn, Bi, Pt,
Au, Ag, W, Cl, Si, P, S, Mo etc. These are bio elements from periodic
table

7. Bio Inorganic chemistry
Study of Inorganic elements in the living systems
Na
11
22.98
K
19
39.09
Ca
20
40.08
Mg
12
24.31
Sodium potassium pump
(1/5th of all the ATP used)
Hemoglobin Vit B12 Hemocyanin Carbonic anhydrase
Myoglobin Carboxypeptidase
Cytochromes
Ferredoxin
Cu
29
63.55
Zn
30
65.38
Fe
26
55.85
Co
27
58.94

8. 1. Regulatory Action Sodium potassium channels and pump
Na, K Nerve signals and impulses, action potential
muscle contraction
2. Structural Role Calcium in bones, teeth
Ca, Mg provide strength and rigidity
3. Electron transfer agents Cytochromes: redox intermediates
Fe2+/Fe3+ membrane-bound proteins that
contain heme groups and carry out electron
transport in Oxidative phosphorylation
4. Metalloenzymes Carbonic anhydrase, Carboxypeptidase
Zn biocatalysts, CO2 to HCO3
,protein digestion
5. Oxygen carriers and storage Hemoglobin, Myoglobin, Hemocyanin
Fe, Cu 18 times more energy from glucose in
presence of O2
6. Metallo coenzymes Vitamin B 12
Co biomethylation
Important roles metals play in biochemistry

9. ESSENTIAL AND TRACE ELEMENTS IN BIOLOGICAL
PROCESSES :
• There are some essential bioinorganic materials in that some of them
are used in trace amount as trace elements in metabolism of living
organisms.
• These are classified into essential and non essential elements
according to their action in the biological system.
• 1.Essential Elements
• 2. Non-essential elements
• 3. Toxic Elements.

10. 1.Essential Elements
• These are very essential/necessary for life processes.
Ex:
• C, H, N, O – Bulk elements
• Na, K, P, S, Ca, Cl, Fe, Mg – Macronutrients or required in relatively
large amounts.
• Mn, Co, Cu, Ni, V, Cr, Mo, F, Al, Pb, Sn, Zn,Si – Micronutrients (trace
elements).

11. • 2.Non- Essential Elements
• These are not essential. In their absences also living organisms May
serve the same function.
• Ex: Al, Sr, Ba, Sn etc.,
• 3.Toxic Elements:
• These elements disturb the natural functions of biological system. Our
human body is made up of 99.9% of just 11 elements disturb the
natural functions of biological system.
• Our human body is made up of 99.9% of just 11 elements in that 4
are hydrogen, oxygen, carbon, nitrogen with 62.8%, 25.4%, 9.4% and
1.4% respectively.
• Ex: Pb, Cd, Hg etc.,

12. Deficiency diseases
• (Methyl mercury) minamata discote (loss of vision, Paralysis, made
weakness)
• Cd-Cd poisoning causes – Kindney failures, bone softening’s – by
mining companies to rivers. Itai – Itai disease (Japan)
• Lead– lead based points, dust, cigarette smoke, household, Industrial
dust all human body can damage.

13. METALLOPORPHYRINS:
• Metalloporphyrine are important biochemical compounds.
• These is nature are conjugated to proteins and form many important biologic compounds.
• Ex: Iron containing haemoglobin molecules which bind to oxygen and acts as oxygen
transporters in vertebrates.
• Generally these porphyrins combined with metal like copper, zinc, iron, magnesium,
silver etc.
• Ex: Haemoglobin. It is a pigment present in red blood cells.
• These absorb the intensive colour bands in visible region and due to this these are deeply
coloured porphyrins – Greek word – Purple.

14. STRUCTURE AND FUNCTIONS OF
HAEMOGLOBIN:
• Haemoglobin is a globular haemoglobin protein in red blood cells (RBC) which transports oxygen
from the lungs to the peripheral tissues of the body mainly it is responsible for the red colour of the
blood cells.
• Heme is an iron (II) complex of protoporphyrin IX ligand. Haemoglobin carries oxygen efficiently
from lungs to the tissues in the body. It also aids the transporting hydrogen ions and carbon dioxide
back to the lungs.
• It composed of 4-subunits each containing a Co-factor known as heme group that induces an iron
atom centre.
• Haemoglobin tightly binds oxygen from the lungs, carrier it from the lungs to the peripheral tissues
of the body, after unloading oxygen at the peripheral tissues, it binds carbon dioxides and returns it
to the lungs to exhaled. It contains 2 protein sun units; 2ά & 2.

15. STRUCTURE AND FUNCTIONS OF
HAEMOGLOBIN contd..
• Abnormalities causes a variety of disorders like sickle cell anaemia (RBC become
misshapen and broken down; RBC converts in sickle shape, cells die., early, leaving a
shortage of healthy red blood cells and can block blood flow causing pain or sickle
cell crisis .
• Thalassemia (It is hereditary haemolytic disease caused by faulty haemoglobin
synthesis, widespread mainly in Mediterranean, African and Asian counties.
• It is mainly caused by mutations in the DNA of cell that makes haemoglobin; this
may pause from parents to children’s).

16. STRUCTURE OF HEME :
• Str: It contains 4 polypeptide units; 2 and 2 chains each with 141 and 146 amino acid respectively.
• A heme molecule is a cyclic molecule that consists of nitrogen carbon and hydrogen atoms with a Fe+2
ion located in the Centre.
• In a molecule, 4-nitrogen molecules hold the iron in the centre. This iron informs the bonding with a
histidine side chain from one of the subunits, which forms the pocket.
• These iron ion bonds to histidine 87 in  chain and histidine 92 in -Chain.
• Here both  and  87, 92 are part of F helix in each submit. The total molar mass of haemoglobin is
about 64, 500.

17. STRUCTURE OF HEME :

18. STRUCTURE OF HEME :
• The O2 does not oxidize haemoglobin considering the redox potentials
for the reduction of O2 and Oxidation of Fe+2. The reversible binding
of O2 in haemoglobin is due to the porphyrin ring system and
hydrophobic blocking of large protein (globin). Here a porphyrin ring
system with Co-ordinated iron (heme group).
• Here “globin” from haemoglobin refers individual protein subunits.
Subunit of this each, contains mainly and helices with no beta stands.
Each sub unit folds into 8- helical segments which forms a pocket
that holds the heme.

19. Protoporphyrin IX and Heme
15 different ways to arrange the substituents around the porphyrin. Only one
isomer protopophyrin IX is found in the living system. Porphyrins are planar
and aromatic

20. Proteins –consists of different amino acids in a specific sequence connected by the peptide
bond –

21. Hemoglobin molecule:

22. Inorganic Prosthetic group of three well known oxygen carriers
Present in
Vertebrates
Present in
molluscs
Present in some sea
worms

23. Can the prosthetic unit part of a metalloprotein perform its normal function
without the protein unit around it ?
Fe2+
Free Heme
+ O2 Fe2+ O
O
Fe2+ O
O
Fe2+
+ 2 Fe4+ O
Fe4+
O Fe2+
+ Fe3+ O
Fe3+
Reversible binding of O2 is possible on when protein
unit is present around the heme unit

24. STRUCTURE AND FUNCTIONS OF CHLOROPHYLL:
• It was first isolated by Joseph bienaime Caventou and Pierre Joseph Pelletier in
1817.
• It is a molecule present in green plants, absorbs sunlight and uses its energy to synthesize
Carbohydrates from CO2 and water, this process is known as photosynthesis or light driven
process is the base for all life processes of plants.
• It is derived from Greek work Chloros means green and phyllon means leaf. It allows plants to
absorb energy from light and it converts light energy into food (Carbohydrates) in the plant.
• Photosynthesis Reaction:
• 6CO2 +6H2O C6H12O6 + 6O2( in pr. Of light energy)
• Chlorophyll absorbs light strongly in the blue portion of electromagnetic
spectrum followed by red portion.

25. STRUCTURE OF CHLOROPHYLL

26. STRUCTURE OF CHLOROPHYLL
• The principal photo receptor in the Photosynthesis reaction is chlorophyll. Mainly it is
found in the chloroplasts of green plants [It is the site of Photosynthesis in algae and
higher plants] these are mainly located in mesophyll cells of the stem and leaves it
contains mainly membrane, strong, grana
• It is region for green color of the plants. The basic structure of Chlorophyll molecule
is a porphyrin ring co-ordinated to a central atom. Group function in haemoglobin
except that in heme central atom is iron, whereas in chlorophyll it is magnesium. It is
Macrocyclic tetrapyr role, derived biosynthetically from protoporphyrin IX, differs
from heme in 4-major respects.

27. STRUCTURE OF CHLOROPHYLL

28. BIOLOGICAL ROLE OF SOME METAL IONS:
• Metal ions play an important role in human beings system. The
concentration of metalions, their control is generally exercised by
some biological complexing agents. And the deficiency or excess of
metal ions causes disorder, which leads to various diseases.

29. Biological Role of Na:
• Sodium is the one of the most predominant extracellular cation in the
animals and man. Generally human body has about 105 grms of Na in
adults and about 24% is located in the bone and 65% in cellular level
water. The sodium ion equilibrium is maintained by kidney (electro
cycle balances).
• Sodium mainly founds in fluids occurs in cells. These sodium ions
have some main functions like:

30. Biological Role of Na:
• It controls the osmotic pressure and equilibrium in acid base system.
• There ions have important role in metabolism on water in the body.
• In blood stream 93% of Na ions (bases) found.
• They have main specific role in the absorption of Carbohydrates.
• They also has an effect on muscle irritability.
• These Na ions in term of NaCl plays an very important role in human
body, NaCl (salt) is the main dietary source needed to human body.
The excess intake of Na may cause elevation in blood pressure (hyper
tension/high B.P) and reduced Na intake causes and controls the high
blood pressure.

31. Role of Na+:
• It is an excellent fluid.
• In human body it plays an important key role in regulation of blood volume, B.P. Osmotic pressure and
maintains constant pH.
• It balances the pressure/Osmotic pressure so it is also known as “Sodium pump” of the human body.
• It plays a main role in the equilibrium of acids and bases.
• Proteins, Amino acid, Nucleic acids are confirmed by this Na.
• Nerve system impulsion can be electrically balanced by these Na+ ions.
• It has main role in functioning of neurons and Osmo regulation between cells and extra cellular fluids.
• In sufficient sodium in our blood may cause hyponatremia. Lack of sodium may cause kidney diseases an
enlargement in heart muscles and headache Osteoporosis, stomach cancer etc., Too much sodium can also
affect the appearance/vision.

32. Biological Role of K:
• K is found in most animal and vegetable foods. An adult human has
approximately 140 grms of K in intra cellular water as cation. Since
muscle contains most of the body’s intra cellular water, it also
contains K.
• Like sodium potassium has stimulating effect on muscle irritability.
• K required for protein synthesis, glycogen preparation and metabolic
break down of glucose.
• Potassium is one of the major cation present in intra cellular fluid and
it regulates intra cellular Osmatic pressure, acid base balances.
•

33. Biological Role of K+:
• As a major component for protein synthesis and RNA replication.
• Secretion of gastric acid is from K.
• Acts enzyme activators.
• Act as Trans membrane potential.
• It helps to regulate fluid balance, muscle contractors and nerve
signals.

34. Biological Role of Fe:
• Iron is an essential component present in haemoglobin and myoglobin. Our body
contains about 4-5 grms of Fe 60-70% of Fe present in haemoglobin in red blood
all.
• Iron is essential for various enzymatic system like cytochroma, eatalses,
peroxidises, succinic dehydragenase etc.
• Iron is essential for oxygen and electron transport within the body. Role of Fe, Cu,
Mo.
• Electron transfer.
• Oxidation -reduction of proteins.
• Nitrogen fixation

35. Biological Role of Fe:
• Redox reactions of enzymes
• Proteins with oxygen.
•
• 3-5% is in muscle myoglobin.
• 12-15% is in protein in cellular level.
• 0.004% is bound to the serum transport protein
• to 0.2% is in respiratory enzymes
•

36. Deficiency Diseases:
• May cause anaemia because of red cells of blood with low level of
haemoglobin than the normal level.
• Acute iron poisoning leads to vomiting shock, collapse, pallor and
coma.
• Higher iron deposition yellowish of skin/unhealthy pale appearance in
tissues and organs may also affect the body is known as siderosis.

37. Biological Role of Zn:
• Zinc is an active component or cofactor for many enzymatic reactions.
Mainly in lipid, protein, carbohydrates metabolism, several
peptidases, oxalacetic decarboxylase.
• In wound healing this Zn plays an important role and for hormonal
activities like insulin, glucagen corticotrophin, FSH and LH Zn plays a
vital role.
• More than 80 metalloenzymes in living organisms includes the Zn for
Carbonic an hydras (CO2 transportation in blood and for secretion of
HCl acid in stomach), pan creatic carboxypeptidase, tryptophan
desmolase, alkaline phosphatise etc.

38. Deficiency of Zn:
• In human beings, mainly in an adult body zinc is present as 1.5 – 3.0
grms in liver and bone.
• Zn efficiency found in an in heriated form in many infants is known as
acrodermatitis enteropathica.
•
• Deficiency may cause behavioural disturbances.
• Diarrhoea, hair loss, skin rashes, weight loss etc.

39. Role of Zinc:
• As a lewis acid [Electron pair acceptor (H+)] H+ - chat can accept a pair
of non-bonding electrons].
• As metallo enzymes.
• Structure promoters for proteins.

40. Glycolysis + Oxidative phosphorylation: How food is converted into energy
Glucose + 36 ADP + 36 Pi + 36 H+
+ 6 O2 6 CO2 + 36 ATP + 42 H2O
Glucose gives 18 times more energy when oxidized
ATP + H2O ADP + Pi + H+ + energy  G0
= - 7.3 kCal/mole
Different forms of Cytochromes (except
Cytochrome P-450) are involved in the
electron transfer process leading to ATP
synthesis and conversion of O2 to H2O
See youtube video ‘cellular respiration ( electron transfer chain)’
ATP : Universal currency for energy
in living systems

41. 

141 Amino acid
146 Amino acid
Mb 153 Amino acid
Hemoglobin Hb
Four units of Hb
See youtube video ‘Oxygen Transport’
3 major types of
Hb
Hb A (Adult)
Hb F ( Fetal)
Hb S (Sickle cell)
Hb is not an exact tetramer of Mb

42. N
N
N
N
Fe
Fe
DEOXYMYOGLOBIN OXYMYOGLOBIN
N
N
H
Protein
N
N
H
Protein
N
N
H
Protein
N
N
H Protein
Proximal
histidine
Distal
histidine
O
O
Fe2+
t2g
4
eg
2
, HIgh spin, radius 92 pm Fe3+
t2g
5
eg
0
, Low spin, radius 75 pm
Paramagnetic Diamagnetic
Fe 42 pm outside porphyrin plane Fe fits inside the porphyrin plane
Basics of oxygenation remains same for Hb and Mb. But there
are some differences in the way the four units get oxygenated.
This begins with pulling of the proximal histidine when Fe gets
inside the plane of the porphyrin ring upon oxygen binding

43. Hemoglobin S (Sickle Cell Anaemia)
Sickle-cell anaemia is caused by a mutation in the β-globin chain of haemoglobin, causing a hydrophilic
amino acid glutamic acid to be replaced with the hydrophobic amino acid valine.
In areas where malaria is a problem, people's chances of survival actually increase if they carry sickle-cell trait (Carrier).
The malaria parasite has a complex life cycle and spends part of it in red blood cells. In a carrier, the presence of the
malaria parasite causes the red blood cells with defective haemoglobin to rupture prematurely, making the plasmodium
unable to reproduce. The polymerization of Hb S affects the ability of the parasite to digest Hb.
See youtube videos ‘Sickle Cell’ and ‘Sickle cell disease’

44. QUESTIONS:
• 2 marks questions:
• Define bioinorganic molecules.
• Mention any 2 biological functions of Na+ and K+.
• Mention biological function of Iron.
• Name essential and trace elements in biological process.
• What are metalloporphyrin? Give an example.
• 5 marks questions:
• Explain structure and biological function of Haemoglobin.
• Write a note on biological functions of metal ions in the human body.
• Explain structure and biological functions of chlorophyll.