Bio-inorganic chemistry
11.1. Introduction:
Bio-inorganic chemistry is a branch of chemistry which deals with the study of inorganic substances (like metals) in the living system in terms of various aspects like transport structural support defense, therapeutic action, enzymatic action, toxicity, nutrition, etc.
Previously, the classical concept of study was that inorganic chemistry deals with non living thing and organic chemistry deals with materials living organism. Biochemistry introduced a new strategy in the perception of study about living and non living matters in this new paradigm. It shifted the classical concept of inorganic and organic chemistry by dealing with inorganic matters in the organic substances. Biochemistry broadly studies of roles, effects, metabolic action, structural supports of inorganic substances like metals, non metals in the living organism. Several natural organic substances include different inorganic elements. Metalloenzymes, peptidases, phosphatase, haemoglobin, chlorophyll, coengymes, vitamins, antibiotics and biominerals are some examples of organic compounds that contain metals. Some biological systems also contain less concentration of elements like iron, chromium, vanadium, manganese, cobalt, nickel, zinc, copper, molybdenum, boron, silicon, selenium, fluorine, iodine, strontium, barium, tungsten etc.
In the nineteenth century, the nutrient metabolism of phosphorous, nitrogen and potassium was studied and utilized in the agriculture. The studies of haemoglobin (contains Fe), chlorophyll (contains Mg), vitamin B12 (contains Co) helped to understand important roles of inorganic elements in the living matters. An inorganic compound cis-Pt(NH),Cl, is being used in therapy of certain types of cancers like ovarian cancer, breast cancer.. testicular cancer, cervical cancer, bladder cancer, esophageal cancer and lung cancer. Nowadays, the study of inorganic elements in the biological system has attracted keen interest.
11.2 Micro and macro nutrients:
Micro nutrients:
The nutrients which are required in small quantity for the normal growth, health and survival of organism are called micro nutrients. For example, minerals, antioxidants and vitamins are called the example of micro nutrients.
Macro nutrients:
The nutrients which are required in large quantity for the normal growth, health and survival of organism are called macro nutrients. For examples, carbohydrate, lipid, protein, fiber and water are the example of the macro nutrients.
Importance of macro nutrients in organism:
Carbohydrate, fats and protein are the sources of energy. Lipids are essential in making cell membrane. Protein is required for building and repairing tissues. It is required to make enzymes, hormones and essential chemical substances in body. Fiber is required to regulate bowel movement, improve blood sugar level and cholesterol, eliminates toxins. Human body contains about 70% water by weight. Water is essential for breaking down of food molecules to generate energy, regulation of metabolism and dissolution of compounds etc.
|
Macronutrients |
Main Function |
Main Sources |
|
Carbohydrates |
Provides and stores energy, builds macromolecules and spares the use of protein. |
Oat, barley, wheat, rice. |
|
Protein |
Oxygen transport, enzymatic activity, antibodies making, providing structures, movements in muscle, cell signaling. |
Dairy, meat, fish, beans, lentils, soy products, eggs, etc., |
|
Lipid()fat |
As structural component of cell membrane, storing energy, signaling, fatty acid metabolism, transpiration of chemical substances etc. |
Vegetable oil, meats, butter, milk, cheese, etc. |
|
Fiber |
Regulation od bowel movement, improvement of body sugar level and cholesterol, help in eliminating toxins, body weight control, keeping optimal PH in intestine. |
Oat, barley, grain bread, melon, orange, berry, broccoli, carrots, bean, pulse etc. |
|
Water |
Regulation of temperature and PH, protection of spinal cord joints, removal of body wastes, dissolution of mineral, absorption of nutrients etc. |
Drinking water, food, fruits, juices, beverages etc. |
Importance of micro nutrients in organisms:
Vitamins are necessary in the use of energy, regulation body functions, keeping the body healthy and promoting resistance to diseases. The deficiency of vitamins may lead to diseases or death. Organism requires vitamins for immune system, energy production and various other functions.
Minerals are essential for proper bone growth, maintenance of proper blood pressure, fluid balance
etc.
|
Minerals |
Main Functions |
Main Sources |
|
Iron |
Oxygen carrier providing oxygen to muscles. |
White beans, spinach, oysters. |
|
Manganese |
Metabolism of carbohydrates, amino acids, cholesterol. |
Pineapple, Peanuts |
|
Copper |
Formation of connectives tissue, nervous system. |
Liver, Cashews, Crabs |
|
Zinc |
Immune system and normal growth. |
Oysters, Crab |
|
Iodine |
Thyroid regulation |
Seaweeds, Yogurt, cod |
|
Fluorine |
Development of bone and teeth. |
Crab, Water(as fluoride salt) |
|
Selenium |
Protection against oxidative damage, thyroid function. |
Brazil nuts, ham, sardine |
Difference Between Micro nutrients and Macro nutrients:
|
Macronutrients |
Micronutrients |
|
They are required in large quantity for normal growth and survival of
organism. |
They are required in small quantity for normal growth and survival of organism. |
|
They include both minerals and non-minerals. |
They includes only minerals. |
|
They essentially provides energy and body structures. |
They mainly essential for regulating body functions and defense system. |
|
Their deficiency cause malnutrition, kwashiorkor etc. |
Their deficiency cause goiter, anemia etc. |
|
Their overdose cause hypertension, diabetes, obesity etc. |
Their overdose cause damage of liver, bones, nerve center etc. |
|
They have large abundance in almost all plants and animal products. |
They are found in small quantity in selected plants and animal products. |
|
Carbohydrates, protein, lipids and water are the example of macronutrients. |
Vitamins, minerals and antioxidants are the example of micronutrients. |
11.3 Importance of metal ion in biological system:
Some metal ions and their importance in biological system are discussed here.
1. Sodium metal (Na):
Sodium ion (Na) is found in body fluid. It helps to maintain blood volume and blood pressure.
It balances the electric charges of the cell and maintains the osmotic pressure inside the cell so as to prevent the chance of collapse of the cell. It also assists the movement of glucose into cell. Sodium along with potassium ion is necessary to transmit nerve impulses. Very low percentage of sodium ion in blood may cause headache and coma. Its high percentage in the blood increases high risk of heart failure, osteoporosis and kidney diseases.
2. Potassium (K):
Potassium ion along with sodium is responsible for nerve impulses. It helps in muscle contractions, heart beat and reflexes. It also helps in regulating the fluid balance in the body.
Low concentration of potassium may cause minor problem like weakness, muscle cramp. palpitation, mood swing and breathing difficulties. It helps in photo synthesis by regulating opening and closing stomata. It helps in production of ATP.
3. Magnesium (Mg):
Magnesium ion is essential in catalyzing more than 300 biochemical reaction in the body. It helps in supporting healthy immune system, keeping heartbeat steady, adjusting proper blood sugar level and supporting the production of protein and energy. It helps in healthy brain development. In plant, it is major element of chlorophyll and helps in photo synthesis, Low intake of magnesium may cause weakness and depression.
4. Calcium (Ca):
It is essential for making strong teeth and bones. It plays important role in muscle contraction, fluid balance, regulation of nerve impulses, regulation of proper heart beat and blood clotting. It helps in improving the cholesterol level. Deficiency of calcium can cause alternation of dental structure and brain, cataract and osteoporosis. In plants, it is necessary for the cell wall.
5. Iron (Fe):
It acts as oxygen carrier in the blood. Haemoglobin transports oxygen in the blood and myoglobin stores and releases oxygen to sustain aerobic metabolism in the muscle of marine animals. Iron is also an important lement in several enzymes like aldehyde oxidase, peroxidase, succinic dehydrogenate etc. Its deficiency in body can cause decrease in RBC. In plants, it is important as an constituent of some enzyme and pigments.
6. Copper (Cu):
It is important element in metalloenzymes which catalyses various biochemical reactions. Copper is also an important element in some metallproteins. Copper proteins are found in almost all terrestrial life. They are useful in electron-transfer reactions. Deficiency of protein in the body can cause malfunctions like weakness, premature grey hair, brittleness of bones, memory loss, high cold sensitivity and loss of vision. In plants, it helps in metabolism of carbohydrates, photosynthesis and lignin synthesis.
7. Zinc (Zn):
It plays an important role in cell division, cell growth, healing of wound, carbohydrate digestion and maintenance of immune system. It enhances the action of insulin. It is needed for proper growth of child in infancy and childhood. Zinc plays direct and indirect role for maintaining structure and stability. It is also necessary for gene expression. Deficiency of zine may cause problems like retardation of growth and sexual maturation, loss of appetite, hair loss, and diarrhea and testosterone deficiency.In plant, zinc plays important role
8. Nickel (Ni):
It is found in nucleic acid. It helps in iron absorption, adrenaline metabolism, glucose metabolism, improvement of bone strength. Deficiency of nickel may cause some problem like histological and biochemical change and disturbance in zine and calcium metabolism.
9. Cobalt (Co):
It is integral part of vitamin B. Cobalt helps to absorb and to process cobalamine (B12) which
is cofactor of DNA synthesis. It helps to repair myelin.. a protective layer of nerve cells. It
involves in production of red blood cell. It also helps to stimulate the production of thyroxine,
Deficiency of cobalt causes the diseases like anaemia and decreased nerve function. In plant, it helps in increasing drought resistance and in nitrogen fixation.
10. Chromium (Cr):
It is necessary in breakdown of carbohydrate and fats. It helps the function of insulin and in thyroid metabolism. It also helps in fatty acid synthesis, RNA synthesis and cholesterol synthesis. Deficiency of it can cause malefactions like weight loss, reduction in breakdown of glucose and impaired coordination. In plants, chromium helps in regulation of carbohydrate metabolism.
11.4 Ion pumps:
The trans membrane protein that transports ions across a biological membrane (cell membrane) against concentration gradient of the ion via active transport is called ion pump.
The transport of ions across a membrane from a region of lower concentration to higher concentration is termed as active transport. It is a transport of ion against the concentration gradient. Active transport proteins are of two types; primary active transport protein and secondary active transport protein.
The transporters (active transport proteins) that transport the ions like Na, K, Ca using ATP as the source of energy are called primary active transport proteins or primary active transporters.
Sodium-potassium pump is an example of primary active transport protein.
The transporters (active transport proteins) that transport ions using potential energy from the concentration gradient created by the primary transporters are called secondary active transport proteins or secondary active transporters. Sodium glucose pump is an example of secondary active transport protein
Sodium-Potassium Pump:
This sodium-glucose pump is an example of secondary active transport and is active in intestinal as well as kidney cells. This pump transports glucose into interior of the cell from extracellular fluid against concentration gradient. The energy required for this transport is come from potential energy of concentration gradient of sodium ion, which is already created by the sodium-potassium pump (the primary active transport),
As the function of sodium-potassium pump in the primary active transport, the concentration of sodium ions increases in the extracellular fluid than in the interior fluid of cell which creates concentration gradient and allows sodium ion to move inside the cell along with glucose. The potential energy developed by concentration gradient is utilized for the active transport of glucose into the cell from extracellular fluid. Therefore, sodium-glucose is secondary active transport. Glucose is essential and necessary in the cell to provide energy for various cell functions.
11.5 Metal Toxicity:
The toxic effect of metals in their certain oxidation states and certain doses, on the life of organism is called metal toxicity
Many heavy metals are toxic and most of the metals are toxic in beyond certain doses. Metals in certain oxidation state may be more toxic than another oxidation state. For example, trace amount of Cr (III) is an essential whereas Cr (IV) is a carcinogen (cancer causing). Some of the light metals may also be lethal (deadly) in certain conditions. Some radioactive isotopes are found to be deadly Toxic,
One thing to be noted that toxic metals can't be easily removed unlike the organic toxic compound since metals get accumulated.
Toxic effect of some metals:
1. Toxicity of Iron (Fe):
The tolerable upper intake level of iron for an adult is 0.8mg/Kg by weight per day.
The concentration above 350-500ug/dl in the blood is considered to be toxic. However, the permissible limit depends upon the age, sex, and biological conditions.
i. Excess iron in body can catalyze reactions of formation free radicals that can damage biomolecules, cells and tissues.
ii. Excess iron can corrode lining of the gastrointestinal tract which can cause damage of liver and brain
iii. Excess iron may cause liver cirrhosis (disruption of liver structure), liver cancer, depression, hypothyroidism, heart attack, diabetes, hair loss, infertility, testosterone hormone deficiency etc.
iv. Over loaded of iron causes serious problems like multiple sclerosis (hardening of tissue). Alzheimer's disease (memory loss, impaired thinking), Parkinson's disease and epilepsy.
v. In plant, iron toxicity causes stunted growth, bronzing (discoloration) of the foliate and stippling of leaves (dots and flicks).
Ground water containing high concentration of iron, supplemental iron, certain tonic of children and pregnant women are the sources of iron overdoses.
2. Toxicity of Arsenic (As):
The tolerable upper intake level of arsenic for an adult is 0.3 ug/Kg by weight of body per day. According to WHO guidelines, the arsenic more than 10 ug/L in drinking water is harmful.
i. Arsenic poisoning causes headache, diarrhea and drowsiness (sleeping).
ii. The excess poisoning can causes the malfunctions like simple vomiting, vomiting of blood, cramping muscles, hair loss,, stomach pain and loss of blood in the urine.
iii. Arsenic poisoning may also cause cancer of lungs, kidney and liver and even coma death.
iv.The chronic arsenic toxicity (Arsenoicosis) causes darkening of skin, thickening of skin, skin pigmentation, skin lesions (abnormal change), heart disease and night blindness.
v. In plant, arsenic poisoning causes problem like stunted growth and low crop production.
Arsenic is found in arsenates, arsenates, oxides and sulphides form. Some plants, arsenic containing industrial disposal, some metallurgical process and ground water contaminated with pesticides are the sources of arsenic poisoning.
3. Toxicity of Mercury (Hg):
Mercury is highly toxic and bioaccumulating metal found in nature in various forms like metallic mercury, its inorganic salts and mercury containing organic compounds. The tolerable upper intake limit of mercury for an adult is 5 ug/Kgbody weights per week. The level of mercury in drinking water higher than 0.001 mg/L is supposed to be toxic. Mercury mainly attacks on brain, kidney and muscles.
i. Mercury is neurotoxic and can cause malfunctions like mitochondrial damage. microtubule destruction and lipid peroxidation.
ii. It can cause neurological disorder like memory loss, emotional instability asomnia (staying asleep)
iii. Mercury vapours may cause health problems like bronchitis, vomiting, skin rashes, respiratory problem and increased blood pressure.
iv. In plants, mercury poisoning causes adverse effect on seed germination, embryo growth.
transpiration and photosynthesis.
Mercury polluted water, agricultural activities, municipal and industrial waste water, mercury in barometers, mercury in are lamp, mercury in amalgams, mercury in thermometer and various mining activities are the sources of mercury poisoning.
4. Toxicity of Lead (Pb):
The tolerable upper intake level of lead in an adult is 25 ug/Kg body weights per week. In body, lead metal ions can replace ions like Ca, Mg, Fe and Na causing disturbance in metabolism.
i. The exchange of ions causes disturbance in malfunctions in cellular signaling, ionic transportation, enzyme regulation, protein folding and release of neurotransmitters.
ii. Lead poisoning causes health problems like headache, loss of appetite, hypertension, abdominal pain, dizziness, renal dye function and arthritis.
iii. Chronic poisoning of lead may cause the problems like brain and kidney damage, mental retardation, weight loss, autism (verbal impairment), allergies, paralysis and muscular weakness.
iv. In plants, lead poisoning causes many problems like inhibition of ATP production, lipid peroxidation, DNA damage, inhibition of seed germination, retarded plant growth and diminished chlorophyll production.
Some industries processes, storage batteries, metal plating operation, fertilizers, pesticides, leaded petrol, plumbing pipes, drinking water and domestic wastes are the major sources of lead overload.
5. Toxicity of Cadmium (Cd):
Cadmium is a toxic and bioaccumulated metal. The tolerable upper intake level of cadmium for an adult is 2.5 µg/kg body weight per week.
i. Cadmium gets bound with some protein and amino acid which causes hepatotoxicity, nephrotoxicity and deficiency of iron.
ii. Chronic toxicity of cadmium can lead to serious problems like osteomalacia (softening of bone) and osteomylities (decrease in bone density).
ii. Cadmium fumes may cause chill, fever and muscle ache.
iv. Excessive exposure to cadmium can cause irritation in nose and throat, headache, dizziness, weakness and chest pain
v. It may lead to the health probles like trachea-brochitis, pneumonitis, liver damage nad kidney damage.
vi. In plants, cadmium toxicity causes the problems like stunting leaves and oxidative stress.
Some pigment in paint industries, rechargeable batteries, electrode of alkaline batteries, plastic stabilizers etc are some sources of cadmium overload