Abstract: Fusion proteins or conjugates are provided containing an amino acid sequence having a substrate binding region of a polysaccharidase such as cellulase that binds to a .beta.-1,4-glycan matrix such as cellulose. The substrate binding region is essentially without polysaccharidase activity. In the fusion protein, the substrate binding region is fused or chemically linked to a polypeptide such as an enzyme, a hormone, an immunoglobulin or a protein dye. By contacting the fusion protein with a .beta.-1,4-glycan matrix, the substrate binding region binds to the matrix to immobilize the polypeptide on the matrix. The polypeptide or fusion protein can be removed from the matrix with a protease recognition sequence or with a solution having a low ionic strength or high pH. In the conjugate, the substrate binding region is joined such as by covalent bonding to a non-protein chemical moiety such as a dye, chromophore, fluorescor, radionuclide or enzyme co-factor. By contacting the conjugate with a .beta.

Abstract: A fusion protein that can function as a removable label is prepared containing a polypetide such as an enzyme and an amino acid sequence having a substrate binding region of a polysaccharidase such as cellulase that has essentially no polysaccharidase activity. By contacting the fusion protein with a .beta.-1,4 glycan matrix such as cellulose, the substrate binding region binds to the matrix to immobilize the polypeptide. The polypetide or fusion protein can be removed from the matrix with a protease capable of cleaving a specific protease cleavage site, or with a solution having a low ionic strength or a high pH. The fusion protein can be prepared by recombinant DNA technology.