Insulin is a globular protein that functions in cell signalling. It is carried in the blood plasma from the cells that make it to its target cells. One molecule of insulin contains six sulfur-containing amino acids and consists of two polypeptide chains. Which of the following statements about insulin are correct? 1. An insulin molecule has a quaternary structure. 2. Insulin polypeptides are held together by six disulfide bonds. 3. Amino acids with hydrophobic R groups would be found in the centre of an insulin molecule.
- A1, 2 and 3
- B1 and 2 only
- C1 and 3 only
- D2 and 3 only