Enables serine-type endopeptidase activity. Involved in complement activation, lectin pathway. Located in extracellular space. Is expressed in several structures, including alimentary system; brain; genitourinary system; liver; and spleen. Human ortholog(s) of this gene implicated in 3MC syndrome 1. Orthologous to human MASP1 (MBL associated serine protease 1). [provided by Alliance of Genome Resources, Apr 2022]