Abstract: A proteolytic enzyme isolated from human tissue which exhibits a proteolytic activity to hydrolyze Met-Asp peptide bond in an amyloid-like substrate is disclosed. This enzyme has been designated "amyloidin" because it proteolytically cleaves a Met-Asp bond similar to the one present in the amyloid precursor protein to release a fragment having the mature Asp terminus of the .beta.-amyloid peptide. Antibodies to the amyloidin protease are also provided. Methods to isolate and purify the amyloidin protease are provided, as well as assays to screen for inhibitors of the amyloidin protease. Also disclosed is the gene encoding the protease and methods for expression of the protease by recombinant DNA means.

Abstract: The present invention provides a stabilized potassium ion-selective membrane comprising lysine-substituted valinomycin covalently bound to a polymeric substrate. The membrane of the invention exhibits improved stability and is used either on ISEs or on solid-state coated wire or semiconductor devices.

Abstract: The present invention is based upon a general principle of providing specific oligonucleotide segments ("linkers", herein) to be attached in sequence to a cloned DNA coding segment. The linkers of the present invention confer desired functional properties on the expression of the protein coded by the coding sequence. Using linkers of the present invention, the desired protein may be expressed either as a fusion or non-fusion protein. A linker coding for an additional sequence of amino acids may be attached, the sequence being chosen to provide properties exploitable in a simplified purification process. A linker coding for an amino acid sequence of the extended specific cleavage site of a proteolytic enzyme is provided, as well as specific cleavage linkers for simpler specific cleavage sites.

Abstract: The present invention discloses novel recombinant DNA cloning vectors for use in Streptomyces and related organisms. These novel cloning vectors contain genetic markers that provide antibiotic resistance or colorimetric selectivity to the host cells. The invention further comprises transformants of the aforementioned vectors.