Human Thrombin Receptor

Updated: 2026-07-17

Overview

The human thrombin receptor (PAR1) is a seven-transmembrane G-protein-coupled receptor that serves as the primary thrombin receptor in platelets and vascular cells. Discovered in 1991, it belongs to the protease-activated receptor family, which is uniquely activated by proteolytic cleavage rather than traditional ligand binding. PAR1 plays pivotal roles in hemostasis, thrombosis, inflammation, and wound healing. In pharmaceutical research, PAR1 is a therapeutic target for antiplatelet drugs (e.g., vorapaxar) and anticancer agents due to its involvement in tumor metastasis. Recombinant PAR1 is commonly produced in HEK293 or CHO cell systems for research applications, with typical yields of 0.5-2 mg/L in optimized expression conditions.

Physical and Chemical Properties

PAR1 is a glycoprotein with a molecular weight of approximately 45-50 kDa, varying by glycosylation patterns. The receptor's N-terminal extracellular domain contains the thrombin cleavage site (LDPR/SFLLRN). Its isoelectric point ranges from 6.8-7.2, and it maintains stability in pH 6.0-8.0 buffers at 4°C for up to 72 hours. Recombinant PAR1 typically exhibits >90% purity by SDS-PAGE and retains functional activity for 6-12 months when stored at -80°C in glycerol-containing buffers. Critical quality parameters include specific activity (measured by calcium flux assays), endotoxin levels (<1EU/μg), and absence of aggregates (verified by size-exclusion chromatography).

Main Applications

In drug discovery, PAR1 serves as a screening target for novel antithrombotic agents, with particular interest in allosteric modulators that avoid bleeding side effects. Academic researchers utilize PAR1 knockout models to study its role in atherosclerosis and tumor angiogenesis. The biotechnology industry employs PAR1 in high-throughput screening (HTS) platforms for cardiovascular drug development, typically using FLIPR calcium assays with sensitivity down to 0.1 nM thrombin. Diagnostic applications include PAR1 expression profiling as a biomarker for metastatic potential in certain cancers (e.g., breast, prostate).

Safety and Storage

PAR1 materials require biosafety level 2 handling due to potential biological activity. Lyophilized preparations should be reconstituted in sterile, endotoxin-free buffers containing 0.1% BSA or HSA to prevent surface adsorption. Working solutions should be aliquoted to avoid freeze-thaw cycles. For long-term stability, store lyophilized protein with desiccant at -20°C (2-year shelf life) or solutions at -80°C (6-month stability). Shipping must comply with IATA PI650 for biological substances. Decontaminate spills with 1% sodium hypochlorite solution followed by 70% ethanol.

B2B Procurement Guide

When sourcing PAR1 for research or production, prioritize vendors providing: 1) Certificate of Analysis with detailed activity data (EC50 typically 0.5-2 nM for thrombin activation), 2) batch-to-batch consistency reports, and 3) regulatory support documentation for preclinical applications. For bulk procurement (>5 mg), request custom expression systems (e.g., insect cell-derived for improved glycosylation) and consider contract research organizations offering functional characterization services. Lead times average 8-12 weeks for GMP-grade material. Negotiate pricing at >10% discount for multi-year supply agreements.