May be specifically involved in the formation of the nacreous layer. Heterooligomer; disulfide-linked. Pif97, Pif80, N16 and other proteins form a complex. Component of conchiolin, the organic matrix of nacre. Expressed at extremely high levels in the dorsal region of the mantle, which region may be responsible for the nacreous layer formation, but only in trace amounts at the mantle edge, which region may be responsible for the prismatic layer formation. Belongs to the N16 matrix protein family.