Molecular Playground/Insulin

איסולין הוא הורמון המפקח על המטבוליזם של פחמימות ומאגרי הסוכר בגוף האדם. הגוף מסוגל לחוש את ריכוז הסוכר בדם ומגיב בהפרשת איסולין. המיוצר בתאי בטא שבלבלב סינטזה של אינסולין הומני בחיידק E. coli הוא חשוב לייצור אינסולין לצורך טיפול בסוכרת שלב 1. פרואינסולין מעובד בתאי הגולג'י לייצר is a hormone that controls carbohydrate metabolism Synthesis of human insulin in E. coli is important to producing insulin for the treatment of type 1 diabetes. Proinsulin (Pins) is processed by several proteases in the Golgi apparatus to form insulin which is shorter by 35 amino acids^[1]. Shortened B chain insulin analogues are: DPI is a monomeric des-pentapeptide (B26-B30) Ins analogue^[2]. DTRI is a monomeric des-tripeptide (B28-B30) Ins analogue. DHPI is for des-heptapeptide (B24-B30) Ins. Leginsulin (LIns) is a legume Ins.

       Insulin is made up of two pieces called the A- and B-chain, shown in grey and green respectively. These two chains are joined by disulfide bonds, which are shown in yellow. This single piece made up of the A- and B-chains is the active form of the insulin hormone. This is the form that binds the insulin receptor on fat or muscle cells in the body, singling them to take up glucose, or sugar, from the blood and save it for later.

       Insulin is able to pair-up with itself and form a dimer by forming hydrogen bonds between the ends of two B-chains. These are shown above in white. Then, 3 dimers can come together in the presence of zinc ions and form a hexamer. Insulin is stored in the in the body. This the hydrophobic (gray) and polar (purple) parts of an insulin monomer at a pH of 7. It is believed that the hydrophobic sections on the B-chain cause insulin aggregation which initially caused problems in the manufacture and storage of insulin for pharmaceutical use.