Surface Plasmon Resonance

SPR Binding Kinetics, Outsourced.

Label-free kon, koff, and KD measurement — sensorgrams and kinetic fit parameters delivered as cleaned CSV files designed for immediate use in computational modeling pipelines.

5–7 days turnaround

Label-free detection

kon/koff/KD kinetic params

Specifications

What you submit. What you get back.

Turnaround

5–7 business days

From purified protein receipt. Surface preparation and regeneration scouting included. Complex targets may require additional time.

Sample Requirements

~50 µg purified ligand

Purified protein for surface immobilization (biotinylated or amine-coupling). Analyte compound or protein at ≥95% purity. DMSO tolerance assessed per run.

Output Format

CSV + sensorgrams

Raw sensorgram data, reference-subtracted traces, 1:1 Langmuir kinetic fit, kon, koff, KD, Rmax, and chi-squared goodness of fit.

AI-Readiness

Kinetic data cleaned for modeling

SPR output from most instruments arrives as proprietary binary files requiring expensive software to open. Litmus delivers cleaned, reference-subtracted sensorgrams and fitted kinetic parameters in open CSV format — directly usable by structural biology and ML pipelines.

Raw and reference-subtracted sensorgrams in plain CSV
1:1 Langmuir kinetic fit: kon, koff, KD, Rmax
Heterogeneous binding model applied where appropriate
Chi-squared residuals for fit quality assessment
Steady-state KD from equilibrium analysis included alongside kinetic KD

                            # SPR result payload
                            assay: "SPR"
                            ligand: "Target-X"
                            analyte: "CPD-017"
                            kinetics: {
                              kon_M_s: 4.2e5,
                              koff_s: 3.1e-3,
                              KD_nM: 7.4,
                              Rmax: 84.2,
                              chi2: 0.41
                            }
                            sensorgram_csv: "..."
                        

Use Cases

Who orders SPR assays from Litmus

Hit Validation & Triage

Confirm binding to the intended target for computational hits before investing in cellular assays. Separate true binders from false positives early.

Lead Optimization & SAR

Measure how structural modifications affect kon, koff, and KD to guide medicinal chemistry decisions with quantitative biophysical data.

Fragment Screening

Screen fragment libraries against a target protein to identify low-affinity binders for FBDD programs that require biophysical confirmation.

Ready to run your SPR?

Tell us your target protein and analyte — we'll confirm surface chemistry and turnaround.

Or email us directly. No spam, ever.