Acollagen-likeproteinwas identi®ed fromtheotolithsof the chum salmon,Oncorhynchus keta. The otolith, composed mainly of calcium carbonate with small amount of organic matrices, is formed in the inner ear and serves as apart of the hearing and balance systems. Although the organicmatrices may play important roles in the growth of otolith, little is known about their chemical nature and physiological func-tion. In this study, amajor organic component of theotolith, designated otolin-1, which may serve as a template for calci®cation, was puri®ed. .
