Why is insulin a hexamer?
Insulin hexamer is such an assembly. While monomer is the biologically active form of insulin, hexamer serves as the storehouse of the hormone. The hexamer also prevents the formation of higher order aggregates.
Is insulin a dimer or hexamer?
View 2: Insulin forms a hexamer. A monomer, consisting of an A chain (green) and B chain (cyan), forms a dimer with another monomer. Three dimers then form a hexamer.
Is insulin polar or nonpolar?
Surrounding its core, the monomer has two extensive nonpolar surfaces. One of them is a flat one that is aromatic and gets buried when there is a dimer formation. The other surface is more extensive and disappears when a hexamer is formed. This is called the quaternary structure of insulin.
Is insulin hydrophobic?
The aggregation of insulin is in fact driven by hydrophobic interaction: the same hydrophobic interaction is also likely the driving force orienting insulin monomers at lipid surfaces.
Why does insulin form dimers?
Insulin molecules have a tendency to form dimers in solution due to hydrogen-bonding between the C-termini of B chains. Additionally, in the presence of zinc ions, insulin dimers associate into hexamers. These interactions have important clinical ramifications.
Is insulin soluble in water?
Insulin is insoluble in water at physiological pH, but dissolves relatively rapidly in plasma. To quantify the ability of various solutions to dissolve crystalline insulin, a simple assay measuring dissolution time was developed.
Is insulin lipophilic or hydrophilic?
Hydrophilic hormones are soluble in water and mediate a faster response than lipophilic hormones. The receptors for these hormones are found on the surface of their target cells. The hydrophilic hormone insulin was the first protein whose amino acid sequence was determined.
What is insulin dissolved in?
Abstract. Insulin is insoluble in water at physiological pH, but dissolves relatively rapidly in plasma.
What is the solubility of insulin?
Insulin has low solubility at neutral pH. It can be solubilized at 2 mg/ml in dilute acetic or hydrochloric acid, pH 2–3. A stock solution can be stored frozen at –20 °C in single-use aliquots.
Is insulin hydrophilic?
This basic fold is present in all members of the insulin peptide family. At the core or center of the molecules is a hydrophobic or “water-hating” or water repellent area. These cluster of hydrophobic residues in the center contributes to protein stability. Stability is also lent by the disulfide bridges.
Is insulin lipid soluble?
Reason : Insulin hormone is lipid-soluble and directily enters inside the cell membrane.
How do you dissolve insulin?
Insulin has low solubility at neutral pH. It can be solubilized at 2 mg/ml in dilute acetic or hydrochloric acid, pH 2–3. A stock solution can be stored frozen at –20 °C in single-use aliquots. Freeze-thaw cycles should be avoided.