Human Cathepsin L/CTSL1 ELISA Kit

From Assay Genie, this sandwich ELISA kit uses a double-antibody format with colorimetric detection for the quantitative measurement of human Cathepsin L (CTSL1). It is validated for use with serum, plasma, cell culture supernatant, cell or tissue lysate, and other liquid samples, and is positioned for research into protein degradation, cell migration, and tissue remodelling. The manufacturer notes that dysregulation of cathepsin L has been implicated in cancer, inflammatory disorders, and cardiovascular diseases, supporting its relevance as a potential biomarker and therapeutic target.

The kit quotes a sensitivity of 37.5 pg/mL and a standard range of 62.5-4000 pg/mL. The workflow involves equilibrating reagents and TMB substrate to room temperature, incubating samples and standards at 37°C for 90 minutes, adding biotin-labelled detection antibody for 60 minutes at 37°C, binding HRP-Streptavidin (SABC) for 30 minutes at 37°C, developing colour with TMB substrate for 10–20 minutes in the dark, and reading absorbance at 450 nm immediately after adding stop solution. Kits are stored at 2-8°C for 12 months. Listed identifiers include UniProt P07711 and synonyms CTSL1, CTSL, cathepsin L, cathepsin L1, CATL, Major excreted protein, and MEP.

Reported validation includes linearity in serum (n=5) of 88-102% at 1:2, 86-103% at 1:4 and 91-103% at 1:8; EDTA plasma (n=5) of 83-95%, 82-88% and 82-91%; and heparin plasma (n=5) of 81-90%, 80-95% and 87-95%. Spike-and-recovery figures stand at 89-104% in serum (average 97%), 89-94% in EDTA plasma (average 92%) and 92-101% in heparin plasma (average 96%).