Globular proteins

Globular proteins are proteins whose individual polypeptide-chain molecules adopt an overall compact, roughly SPHERICAL shape. This spherical shape results from the polypeptide chain coiling around on itself (rather than remaining extended), typically arranging so that non-polar, hydrophobic side chains cluster together on the buried INSIDE of the sphere, away from surrounding water, while polar, hydrophilic side chains sit exposed on the OUTSIDE, in contact with water -- this arrangement is exactly why globular proteins are, as a class, usually SOLUBLE in water (the outward-facing polar surface interacts favourably with the aqueous environment). Well-known examples of globular proteins include insulin (the blood-sugar-regulating hormone), egg albumin (the major pro …