Partial amino acid sequences of organ of Corti proteins OCP1 and OCP2: A progress report

Progress in amino acid sequencing of two low-molecular weight acidic proteins of unknown function which are present at high concentrations in the organ of Corti is reported. These two proteins, provisionally termed OCP1 and OCP2, were originally demonstrated by two-dimendional polyacrylamide gel electrophoresis; their presence at high concentrations in the inner ear sensory epithelia strongly suggests that OCP1 and OCP2 serve some important function in the ear. In the present paper, extension of the amino-terminal sequence of OCP2 to 71 residues is described. In addition, the first results on sequencing of OCP1 are presented. Computer algorithms are used to predict important structural features, and the sequences are analyzed for probable phosphorylation, glycosylation, and Ca-binding sites. Projected further studies in immunochemistry and molecular biology of OCP1 and OCP2 based on the amino acid sequencing data are discussed.