Plasma kallikrein therefore is composed of a heavy chain and a light chain held together by a disulfide bond. The heavy chain originates from the amino-terminal end of the zymogen and contains 4 tandem repeats of 90 or 91 amino acids.
Plasma kallikrein consists of two parts: a heavy chain and a light chain connected by a disulfide bond. The heavy chain comes from the starting section of the inactive enzyme precursor and is made up of four repeated sequences of 90 or 91 amino acids.