Location: San Francisco, CA
Compensation: $150 – 240,000 + equity and comprehensive benefits package
Lead the Chemistry That Decides What Gets Made Next
Helix BioSearch is partnering with an innovative, early-stage biotechnology company in San Francisco built around peptide design and synthesis. The company brings together a mission-driven team with backgrounds spanning world-leading academic institutions, research hospitals and global pharma, and it values speed and rigor in equal measure.
The Opportunity
We are seeking an experienced Senior or Principal Scientist in Peptide Chemistry to lead peptide design and synthesis from sequence selection through production, purification, quality control and biological handoff. This is a highly visible, senior hands-on opportunity for an ambitious chemist who brings clarity to open-ended problems, takes ownership of next steps and wants to grow their scope through contribution rather than title alone.
We are seeking an experienced Senior or Principal Scientist in Peptide Chemistry to lead peptide design and synthesis from sequence selection through production, purification, quality control and biological handoff. This is a highly visible, senior hands-on opportunity for an ambitious chemist who brings clarity to open-ended problems, takes ownership of next steps and wants to grow their scope through contribution rather than title alone.
Key Responsibilities
Lead and scale end-to-end peptide workflows, including sequence design, resin loading, coupling and deprotection, cleavage, purification, characterization and final quality control.
Run, optimize and maintain microwave-assisted solid-phase peptide synthesis (SPPS) systems.
Resolve difficult synthetic and analytical issues, including failed couplings, low conversion, low crude purity, side products and cleavage problems.
Overcome solubility limitations, purification challenges and instrument downtime to keep compound production on track.
Own compound identity, purity, yield and analytical records, ensuring every compound is ready for biological testing.
Interpret SAR, in vitro and in vivo readouts, including potency, stability, exposure, tolerability and efficacy, to design and prioritize next-round compounds.
Improve synthesis, purification and handoff workflows so the team can make high-quality compounds faster and more reproducibly.
Set a high technical bar and communicate risks clearly to the wider team.
Guide and develop other scientists while remaining directly involved in experimental work.
What We're Looking For
Five or more years of hands-on industry experience in peptide, medicinal, organic or closely related chemistry
Strong experimental judgment and deep troubleshooting ability across synthesis, purification, characterization and laboratory instrumentation.
A track record of owning chemistry end to end, from compound or sequence design through to material ready for biological testing.
The ability to work close to biological readouts and translate potency, efficacy, stability, exposure or tolerability data into the next chemistry decision.
A creative, fast and rigorous approach to technical problem-solving and workflow improvement.
The ability to provide technical direction and raise the quality of the team’s work without stepping away from the bench.
Energy, drive and a strong work ethic suited to a fast-moving, early-stage environment.
Why Apply?
Base Salary: $150,000 – 240,000
Generous equity options
Medical, dental and vision coverage
Access to HSA, FSA and 401(k) plans
This is an opportunity to join an ambitious, high-integrity team at an early stage, where you will get close feedback from the people making scientific and company-defining decisions. You’ll play a pivotal role in shaping the company’s peptide pipeline, with real ownership, trust and room to take on increasingly important problems.
If you’re passionate about peptide chemistry, hands-on problem-solving and turning biological data into better molecules, we’d love to hear from you.