A hormone that controls metabolism of carbohydrates and fat in the body and keeps the glucose level of the body in narrow range is known as insulin causes the storage of excess blood sugar as glycogen in liver and muscles. Glucagon is fat insulin stops the release of glucagon. Cognition, vascular compliance is also affected by insulin. Insulin improves the learning capacity, verbal capacity and memory. Insulin composed of 51 amino acid sequence, known as peptide hormone. It's produced by the secretion of pancreas and specifically by islets of langerhans. Its molecular weight is 5808 Da. Latin word insula stands for island i.e. insulin. Primary Insulin structure was successfully explained by Fredrick Sanger in 1951. Active insulin is in the form of monomer but in dormant form in the body it's produced as hexamer.
Production of insulin in body
Pancreas is a gland and insulin is its secretion, produced by the beta-cells of islets of langerhans. It's produced by the endocrine part of the pancreas. Pro-insulin synthesizes insulin in beta cells by the activity of proteolytic enzymes. Enzymes that take part in it are prohormone convertases and carboxypeptidase E. 51 amino acids are in the form of two chains A and B joined together by disulfide bonds. Following steps are involved in it
(1) Translation and translocation
(2) Insulin gene performs transcription
(3) Peptide cleavage by folding, oxidation and signal.
(4) C-peptide is given when proteases is degraded.
(5) Insulin is produced by enzyme carboxypeptidase E.
Insulin is released by beta-cells in two steps. First the insulin release is initiated and in second step it's maintained.
Glucose transporter are the carriers of glucose, enter beta cells with the help of GLUT2. ATP is produced by oxidation by glucose through respiratory and glycolysis cycle. K+ channels close and causes depolarization of cell membrane, this in response causes the Ca+ to flow in cells. Then the cleavage of membrane phospholipids takes place. Insulin is secreted in secretory vesicles caused by the high levels of Ca+. Beta-cells are affected by autonomic nervous system.
Hebert Boyer in 1977 synthesized the first artificial insulin from E.coli. Genes were incorporated in to bacteria and when the bacteria replicated insulin also replicated. It was made for those people unable to synthesize their body insulin hence synthetic insulin was given to them to treat diabetes. Inability of to body to respond against the body insulin produced or to produce insulin is known as diabetes mellitus having 2 types IDDM and N-IDDM. IDDM is youngsters and N-IDDM in mature and aged people. Glargin Insulin is also being produced by the following way. It differs in the end process and purification process.
E.coli is genetically engineered, cultured and grown. By adding inducer they are activated to produce fusion proteins, after the protein synthesis bacteria are killed using disinfectants. Using centrifugation the bacterial residue is first concentrated and then degraded. Centrifugation separates the fusion protein and the residue from each other on the basis of weight and density. After being washed by water it's folded into spatial structure. Fusion proteins are dissolved in aq. Urea for this purpose. Cysteine is used as a protector in this process. Now comes the purification part where insulin is isolated from the urea. And then final purified insulin is obtained. Purified water is used for this process. Earlier insulin was synthesized using bacteria but now the demand for insulin is increasing because the number of diabetics is increasing day by day USA has the largest number of patients suffering from diabetes. Twice the numbers of people die by diabetes alone as compared to the sum of deaths caused by AIDS and breast cancer. Therefore large plants are being used for the production of insulin on industrial scale. A plant was installed in Germany recently.
Insulin is very affective for the treatment of diabetes type 1 in which body fails to produce its own required insulin. Insulin lowers the blood sugar level, transferring the body again to the state of homeostasis. Biotechnology has revolutionized our lives, Insulin was the first drug to be officially to be approved for artificial synthesis after that a large number of drugs are produced now using this technology. In this technique the desired gene is incorporated in the organisms DNA and then when the DNA replicates the desired gene replicates along with it too.
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