Post on 04-Apr-2018
7/30/2019 Bioinorganic Chemistry FKIP
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Bioinorganic Chemistry
Ilham Maulana
Chemistry Dept. FMIPA Unsyiah
7/30/2019 Bioinorganic Chemistry FKIP
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Scope of Bioinorganic Chemistry….
a field that examines the role of metals in biology
includes the study of both natural phenomena such as
the behavior of metalloproteins as well as artificially
introduced metals, including those that are non-
essential, in medicine and toxicology also includes the study of inorganic models or mimics
that imitate the behaviour of metalloproteins
Chemistry Dept. FMIPA Unsyiah
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Major Areas of Bioinorganic Chemistry….
Metal ion transport andstorage
Chemistry Dept. FMIPA Unsyiah
Proteins and small molecules whose
aim is to carefully control the
concentration of metal ions in the cell
(sometimes referred to as metallome)
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Major Areas of Bioinorganic Chemistry….
Metal ion transport andstorage Hydrolase enzymes
Chemistry Dept. FMIPA Unsyiah
a diverse collection of proteins that
interact with water and substrates.
Examples of this class of
metalloproteins are carbonicanhyydrase, metallophosphatases,
and metalloproteinases.
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Major Areas of Bioinorganic Chemistry….
Metal ion transport andstorage Hydrolase enzymes Metal-containing electron
transfer proteins
Chemistry Dept. FMIPA Unsyiah
These electron transport proteins are
complementary to the non-metal
electron transporters nicotinamide
adenine dinucleotide (NAD) and flavin
adenine dinucleotide (FAD).
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Major Areas of Bioinorganic Chemistry….
Metal ion transport andstorage Hydrolase enzymes Metal-containing electron
transfer proteins
Oxygen transport andactivation proteins
Chemistry Dept. FMIPA Unsyiah
extensive use of metals such as iron,
copper, and manganese in
transporting oxygen (Hemoglobin,
Myoglobin). Some metalloproteins are
designed to protect a biological system
from the potentially harmful effects of
oxygen and other reactive oxygen-containing molecules such as
hydrogen peroxide
7/30/2019 Bioinorganic Chemistry FKIP
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Major Areas of Bioinorganic Chemistry….
Metal ion transport andstorage Hydrolase enzymes Metal-containing electron
transfer proteins
Oxygen transport andactivation proteins
Bioorganometallic systems
Chemistry Dept. FMIPA Unsyiah
more focused on the utilization of
metals by unicellular organisms
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Major Areas of Bioinorganic Chemistry….
Metal ion transport andstorage Hydrolase enzymes Metal-containing electron
transfer proteins
Oxygen transport andactivation proteins
Bioorganometallic systems The nitrogen metabolism
pathways
Chemistry Dept. FMIPA Unsyiah
Metals that facilitate the metabolism of
Nitrogen. Nitrogenase is one of themore famous metalloproteins
associated with nitrogen metabolism
7/30/2019 Bioinorganic Chemistry FKIP
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Major Areas of Bioinorganic Chemistry….
Metal ion transport andstorage Hydrolase enzymes Metal-containing electron
transfer proteins
Oxygen transport andactivation proteins
Bioorganometallic systems The nitrogen metabolism
pathways Metals in medicine
Chemistry Dept. FMIPA Unsyiah
the study of the design and
mechanism of action of metal-
containing pharmaceuticals, and
compounds that interact with
endogenous metal ions in enzyme
active sites. This diverse field includes
the platinum and ruthenium anti-cancer drugs, chelating agents, gold
drug chaperones, and gadolinium
contrast agents.
7/30/2019 Bioinorganic Chemistry FKIP
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Metals and Toxicity….
The vast majority of biochemical processes in which a
metal plays a role involve a only a relatively small
number of metals. Those metals include Na, K, Mg,
Ca, Mo, or the fi rst-row transition metals from V to Zn.
(Only molybdenum could be considered as a heavy
metal)
Generally, heavy metals having low charge ( “ soft ” )are toxic (Hg, Pb, Cd, Tl, etc).
Some heavy metals bind to groups such as the
sulfhydryl (-SH) group in enzymes, destroying the
ability of the enzyme to promote the reaction in anormal way
Beryllium is an extremely toxic metal that is not soft
Chemistry Dept. FMIPA Unsyiah
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Metals and Toxicity….
one way that toxicity of metals rises is by substitutionfor another metal (Cd for Zn, Be for Mg…)
When this happens, the enzyme loses its activity
numerous nonmetallic substances that are toxic
(cyanides, carbon monoxide). The toxicity of these
materials is related to their being potential ligands that
attach to metals in specific structures,which thereby
prevents the metals from serving their normal
functions.
Chemistry Dept. FMIPA Unsyiah
7/30/2019 Bioinorganic Chemistry FKIP
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Metals and The Action….
One way in which metals function in biochemicalstructures is in enzyme activity
The function of enzymes as catalysts: Absolute specifi city, Group specifi city, Linkage specifi city,Stereochemical specifi city
Enzymes may not function well or at all unless some
other species known as a cofactor is present The most interesting cofactors are metal ions Mg 2+,
Ca2+, K+ , Fe2+ , or Cu2+
The combination of enzyme and cofactor is known asthe holoenzyme
Chemistry Dept. FMIPA Unsyiah
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Metals and The Action….
One of the most important metals with regard to its rolein enzyme chemistry is zinc (carboxypeptidase A and
B, alkaline phosphatase, alcohol dehydrogenase,
aldolase, and carbonic anhydrase)
Carbonic anhydrase, which contains a single zinc atom
in its structure, has a molecular weight of about 30,000.
In this structure, zinc is surrounded tetrahedrally by
three histidine molecules and one water molecule.
h3ZnOH2 + H2O → H3O+ + h3ZnOH-
h3ZnOH- + CO2 → HCO3- + h3Zn
Chemistry Dept. FMIPA Unsyiah
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Metals and The Action….
Chemistry Dept. FMIPA Unsyiah
Ribbon diagram showing human carbonic
anhydrase II. The grey sphere is the zinc
cofactor in the active site.
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Photosynthesis….
6 CO2 + 6 H2O → C6H12O6 + 6 O2
the reaction requires energy from light, so, it is known
as photosynthesis
The structures that are responsible for absorption of light in order for its energy to be used are the
chlorophylls, which contain porphyrin-type ligands.
The porphyrin structure is derived from the basic unit
known as porphin The chlorophylls consist of several members of a
series, which have structures derived from a molecule
known as chlorin
Chemistry Dept. FMIPA Unsyiah
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Photosynthesis….
porphin chlorophyll
Chemistry Dept. FMIPA Unsyiah
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Oxygen Transfer….
the transport of oxygen by heme is the basis for respiration
Heme is one of several proteins that contain iron
When an oxygen molecule is attached to the iron and it
changes from high spin to low spin, the size of the
Fe2+ changes. The ionic radius of Fe 2+ in the high
spin state is approximately 78 pm, but in a low-spin
environment it is about 61 pm.
This reduction in size is suffi cient to allow the Fe2+
ion to fit between the nitrogen atoms in the porphyrinring.
Chemistry Dept. FMIPA Unsyiah
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Oxygen Transfer….
By the usual standards of coordinate bond strength,
the binding of oxygen to
iron in hemoglobin is quite
weak.
On the other hand, groupssuch as CN-, CO, H 2S,
and others bind strongly to
Fe2+ . Thus these
substances are highly toxic,and they function by
preventing the uptake of
oxygen.
Chemistry Dept. FMIPA Unsyiah