Assay Scientist (JM21-261)

Catalyst Biosciences is seeking an experienced Assay Scientist to join its growing biotherapeutics team at its South San Francisco headquarters. The position will report to our Senior Director of Translational Research. The candidate will contribute to developing novel biotherapeutics and new technologies that move pipeline projects forward and further develop the Company’s protease engineering platform. The position offers an opportunity to make an impact and contribute significantly to a fast-growing company and provides the chance to collaborate across a broad range of disciplines from the earliest drug discovery activities to participating in IND-enabling activities in order to deliver first-in-class as well as best-in-class molecules in the complement and rare disease space. Our new scientist will bring a strong expertise in assay development and the application to the discovery of engineered biopharmaceuticals.


Catalyst is a clinical-stage biopharmaceutical company focused on developing novel protease medicines to address important unmet medical needs in patients with complement related and rare bleeding disorders. We have a versatile protease engineering platform that feeds our research and development pipeline, and this position provides an opportunity to be exposed to the full value chain from early discovery to late-stage clinical trials. To succeed in this role, we expect you to bring an innovative mindset, scientific curiosity, a lot of energy and pragmatism. For more information, please visit


  • Apply your strong knowledgebase and hands-on expertise to develop and establish biochemical and cell-based assays that support screening, optimization, and lead candidate selection in multiple projects in our therapeutic areas of interest.
  • Lead the development of new assay technologies and expand the protease engineering platform to stay at the cutting edge of biologics discovery.
  • Participate actively in the optimization of assay workflows that increase data quality, information content and throughput to meet project goals.
  • Collaborate effectively with colleagues in protein engineering, pharmacology, and drug development to solve complex problems and deliver results within established timelines that meet company goals.
  • Contribute to patent filings and publications as well as present research findings at relevant industry and medical conferences.

**Title and Level to commensurate with education and experience.


  • PhD with experience in biochemistry, chemistry, enzymology, biology or similar fields
  • Sustained record of productivity and substantive scientific contributions as evidenced by high-impact publications, patent inventorship and/or external presentations.
  • Demonstrated experience with a variety of biochemical and cell-based assays (e.g., enzyme kinetics, binding kinetics, immunoassays, receptor signaling, imaging, hemolytic systems)
  • Proven experience with characterization of differentiated lead molecules including but not limited to enzymes, antibodies, multispecifics and other protein scaffolds.
  • Motivated, scientifically driven individual with a creative approach to complex biochemical problem solving.
  • Highly collaborative team player, open to giving and receiving ideas with excellent communication skills and the talent to work effectively within project teams.
  • Ability to think strategically, adapt quickly to changing priorities and have an enthusiasm for new challenges with a desire to focus on efficiency.
  • Keen interest in continued learning in biology, assays and drug discovery.
  • A sound knowledge base in protein chemistry and engineering and/or medicinal chemistry is preferred.
  • Background in complement and rare orphan diseases is a plus.

Thank you for your interest in Catalyst Biosciences! You may apply for this position by sending your CV/resume to, referencing requisition number (JM20-261) in the subject line.