SBIR-STTR Award

Peptide hormones are ubiquitous in nature, and perform cellular functions that are critical to the survival of the organism. Approximately 50 percent of all known peptide hormones are post-translationally modified at the C-terminus by conversion of glycine-extended precursors to the peptide-amide. The enzyme that performs this modification is peptidylglycine alpha-amidating mono-oxygenase (PAM). Inhibition of PAM in various cell types in culture can be accomplished by the addition of specific PAM inhibitors, such as 4-phenyl-3-butenoic acid, resulting in the accumulation of glycine-extended hormone precursors in the conditioned medium. The medium will be fractionated by chromatography techniques and the individual fractions assayed by sequential enzyme reactions consisting of PAM --> glyoxylate dehydrogenase or PAM > glyoxal oxidase --> horseradish peroxidase, to yield a color reaction. In Phase I, we will optimize the enzyme reactions using model glycine-extended substrates, and demonstrate feasibility by the isolation of known peptide hormones from CA-77 cells using this technology. During Phase II, the optimized technology will be used to detect novel amidated peptide hormones in neuro-endocrine cells, and produce the novel peptides recombinantly to obtain material for a series of physico-chemical and functional characterizations. The success of this project will eventually lead to the development of novel therapeutic peptide drugs.

Thesaurus Terms:
amidation /deamidation, enzyme activity, glycine, method development, oxygenase, peptide hormone biological signal transduction, biotherapeutic agent, enzyme inhibitor, posttranslational modification, short chain fatty acid high performance liquid chromatography, mass spectrometry, polymerase chain reaction, tissue /cell culture

Peptide hormones with a C-terminal a-amide functionality are widely important, being found in mammals, insects, cnidarians and plants. The identification of novel a-amidated peptides from a biological source has been significantly hindered by lack of a specific assay for this class of bioactive peptides. Our hypothesis is that numerous a-amidated peptide hormones remain undiscovered. Identification of these novel a-amidated peptide hormones will lead to an increased understanding of cellular signaling pathways and to the role played by the a-amidated peptides in human disease. The novel a-amidated peptides uncovered by our innovative assay could also lead to new therapeutics for the treatment of human disease and/or new tools for the diagnosis of human disease. In Phase I, a novel platform technology (PAM/GO/Luminol chemi-luminescent assay) for the discovery of a-amidated peptides was developed that exploits the unique chemistry of a pro- hormone processing enzyme, peptidylglycine a-amidating monooxygenase (PAM). PAM catalyzes the conversion of glycine-extended peptides to the corresponding peptide-amide. In Aim 1 of this Phase II application, cardiac and prostate cells will be grown in the presence of a PAM inhibitor to accumulate glycine-extended peptides in the conditioned medium. The conditioned medium will be fractionated and analyzed using the PAM/GO/Luminol assay. Fractions identified to contain putative glycine-extended peptides will be further purified and their molecular mass and amino acid sequence will be determined. In Aim 2, the isolated peptides will be characterized to determine if they are derived from unknown genes, and their tissue distribution and abundance will also be determined. Unigene will utilize its proprietary recombinant expression technology to produce milligram to gram quantities of all novel peptides discovered as part of the Aim 3 efforts to enable commercial sales for the research market. The preliminary function of the novel amidated peptide hormones will be elucidated in Aim 4 by a series of in vitro assays and in vivo studies in appropriate rodent models. The long term goal of this project is to perform pre-clinical, toxicology and proof-of-concept clinical studies to determine whether a given novel peptide can be developed for the treatment of diseases that represent unmet medical needs. The clinical development of such commercially viable peptides will be out- licensed to pharmaceutical companies for further clinical development, and for marketing and distribution. Amidated peptide hormones are ubiquitous in the human body and perform important roles in health and disease. Many peptide hormone-based drugs have been successfully developed and are currently in use for the treatment of diseases such as diabetes, osteoporosis, prostate cancer and others. Novel amidated peptides discovery through the use of this technology may find therapeutic applications for currently unmet medical needs and thus lead to the improvement in the well being of the public.

Thesaurus Terms:
Amidation /Deamidation, Enzyme Activity, Glycine, Method Development, Oxygenase, Peptide Hormone Biological Signal Transduction, Biotherapeutic Agent, Enzyme Inhibitor, Posttranslational Modification, Short Chain Fatty Acid High Performance Liquid Chromatography, Mass Spectrometry, Polymerase Chain Reaction, Tissue /Cell Culture