Rabbit Anti-Human CELA3A polyclonal Antibody for ELISA. Elastases form a subfamily of serine proteases that hydrolyze many proteins in addition to elastin. Humans have six elastase genes which encode the structurally similar proteins elastase 1, 2, 2A, 2B, 3A, and 3B. Elastase 3A (ELA3A) is a serine protease which preferentially cleaves proteins after alanine residues. It is secreted from the pancreas as a zymogen and has a digestive function in the intestine. It has very little elastolytic activity.