what is a protein complex
The Bacillus amyloliquefaciens ribonuclease barnase (colored) and its inhibitor barstar (blue) in a complex. A multiprotein complex (or protein complex) is a group of two or more associated polypeptide chains. The different polypeptide chains may have different functions. This is distinct from a multienzyme polypeptide, in which multiple catalytic domains are found in a single polypeptide chain.