Which proteins is used as a chemical defense at body surfaces?

Answer: Antimicrobial proteins.

Explanation:

Antimicrobial proteins are the type of proteins produced by the keratinocytes on the body surfaces. These proteins acts as the barrier and kills the microorganism which is trying to enter the body.

These are larger proteins containing more than 100 amino acids. They are often lytic in nature.

The cell membrane of the microbes is disrupted by the action of these amino acids or proteins on them.