Serpins

Measurement of both native and inactivated forms of α1 proteinase inhibitor in human inflammatory extracellular fluids

“…Carrell & Owen (1985) designated the unstable native configuration as the “S” (stressed) form and the table inactive configuration as the “R” (relaxed) form. On heating at 56°C, the S form of α 1 PI is denatured and precipitates, while the R form is resistant to heat denaturation, even after several hours at 80°C (Carrell et al 1987). The process of α 1 PI polymerisation and subsequent precipitation appears to involve the insertion of the exposed loop of one α 1 PI molecule into a “cleft” between β sheet structures in an adjacent α 1 PI molecule (Lomas et al 1992).…”