Abstract: The present invention provides a synthetic gene encoding the human enterokinase light chain protein, a recombinant vector comprising the synthetic gene encoding the protein, a plant cell transformed with the recombinant vector, a method for producing the human enterokinase light chain protein in a plant by using the recombinant vector, a method for producing a plant producing the human enterokinase light chain protein by transforming a plant cell with the recombinant vector, a plant producing the human enterokinase light chain protein which is produced by the method, and a seed thereof, and a composition for large-scale production of the human enterokinase light chain protein in a plant, in which the composition comprises the synthetic gene encoding the human enterokinase light chain protein.