Dna 2 Essay Research Paper In the

Dna 2 Essay, Research Paper

In the last 10 years, there has been some scientific leaps concerning diabetes, and genetic engineering. The increasing incidence and diagnostic detection of diabetes worldwide coupled with changing trends in the food animal market stimulated people to seek alternative sources of insulin completely independent of an animal-gland source. (Ryan, 1986). The basic recombinant DNA process of formulating insulin was developed. DNA carries the genetic information that determines the fate of each cell. Recombinant DNA technology allows manipulation of bacterial host cells by insertion of genes for production of either the A chain or the B chain of the insulin molecule, or the entire proinsulin molecule. Prior to 1986, the A and B chains of the insulin molecule were produced by separate fermentations (growth of the genetically altered Escherichia coli under controlled conditions). The chains were purified and later combined by chemical techniques to produce insulin structurally and chemically identical to pancreatic human insulin. (Hyde, 1984)

As of 1986, human insulin began to be produced by a process which involves the enzymatic conversion of human insulin’s biosynthetic precursor, human proinsulin. The genetic coding for human proinsulin is inserted into the special E. coli bacteria which are then grown in a fermentation process to produce human proinsulin. With genetic engineering, new proteins are synthesized. They can be introduced into plants or animal genomes, producing a new type of disease resistant plants, capable of living in inhospitable environments. When introduced into bacteria, these proteins have also produced new antibiotics and useful drugs. Techniques of cloning generate large quantities of pure human proteins, which are used to treat diseases like diabetes. In the future, a resource bank for rare human proteins or other molecules is a possibility. For instance, DNA sequences which are modified to correct a mutation, to increase the production of a specific protein or to produce a new type of protein can be stored. This technique will probably play a key role in gene therapy. (Stwertka, 1982)

The insulin hormone is essential for a healthy and normal existence. The insulin molecule consists of two chains of linked amino acids, the A chain containing 21 amino acids, the B chain, 30. These chains are connected by two disulfide bridges (formed of two sulfur atoms each), while a third disulfide bridge stretches across several amino acids on the A chain. The connected chains are partially coiled and twisted into globular structure, a configuration essential for biological activity. Insulin s most prominent effect is to lower blood sugar, primarily by facilitating the uptake and use of glucose by muscle and fat cells and inhibiting the formation of new glucose by the liver. Insulin increases the storage of excess glucose in the form of glycogen. It also stimulates the storage of other energy forms (fat, protein) and inhibits the breakdown and use of these stored materials by the body. (Snyderman, 1998)

Insulin is the most important hormone in intermediate metabolism. When insulin is absent in the body, blood sugar levels rise; muscle and fat cells aren’t able to utilize glucose for energy. It signals the body that it s “hungry”, the liver then releases glycogen (a form of stored glucose). This further increases the blood sugar level. When blood sugar level reaches about 180 mg/dl, glucose begins to spill into the urine. A large amount of water is needed to dissolve the excess sugar, resulting in excessive thirst and urination. Without glucose for energy, the body begins to metabolize protein and fat. Fat metabolism results in the production ketones in the liver. Ketones are excreted in the urine along with sodium bicarbonate, which results in a decrease in the pH of the blood. This condition is called acidosis. To correct acidosis, the body begins a deep, labored respiration, called Kussmaul’s respiration. Left unchecked, a person in this situation will fall into a coma and die. (What is Insulin, 1998)

Insulin is produced by the pancreas that controls the level of sugar (glucose) in the blood and is used in the treatment of diabetes mellitus. The hormone is synthesized in beta cells, which are included in separated groups of hormone-secreting cells of the pancreas known as the islets of Langerhans. Insulin is secreted continually at varying rates and acts in fine tune with hormones (glucagon, catecholamines) that raise blood sugar to maintain blood sugar levels within very narrow limits (about 80 to 100 mg/100 ml of blood). The creation of insulin in the beta cells of the pancreas is a two step procedure. Beta cells first produce preproinsulin. Preproinsulin is cleaved to create proinsulin, which is further cleaved to produce equal amounts of insulin and C-peptide. By measuring the amount of C-peptide in the blood, scientists can determine the amount of insulin produced by the pancreas. A normally functioning pancreas can manufacture and release 40 to 50 units of insulin daily and have several hundred units available in pancreatic storage for release as needed. The pancreas usually stores about 200 units of insulin. The average basal rate for adults is one to two units per hour. After meals, secretion increases to four to six units per hour. (Britannica, 95)

The function of restriction enzyme is importa