title: Quantitative analysis of protease recognition by inhibitors in plasma using microscale thermophoresis.
abstract: High abundance proteins like protease inhibitors of plasma display a multitude of interactions in natural environments. Quantitative analysis of such interactions in vivo is essential to study diseases, but have not been forthcoming, as most methods cannot be directly applied in a complex biological environment. Here, we report a quantitative microscale thermophoresis assay capable of deciphering functional deviations from in vitro inhibition data by combining concentration and affinity measurements. We obtained stable measurement signals for the substrate-like interaction of the disease relevant inhibitor α-1-antitrypsin (AAT) Z-variant with catalytically inactive elastase. The signal differentiates between healthy and sick AAT-deficient individuals suggesting that affinity between AAT and elastase is strongly modulated by so-far overlooked additional binding partners from the plasma.
authors.affiliation: Comprehensive Pneumology Center, Institute of Lung Biology and Disease (iLBD), University Hospital, Ludwig Maximilians University and Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Max-Lebsche-Platz 31, 81377 Munich, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Dau
authors.affiliation: Systems Biophysics and Functional Nanosystems, Ludwig Maximilians University München, Amalienstrasse 54, 80799 Munich, Germany.|Graduate School of Quantitative Biosciences, Ludwig Maximilans University, Feodor-Lynen-Str. 25, 81337 Munich, Germany.
authors.forename: E V
authors.initials: EV
authors.lastname: Edeleva
authors.affiliation: Systems Biophysics and Functional Nanosystems, Ludwig Maximilians University München, Amalienstrasse 54, 80799 Munich, Germany.
authors.forename: S A I
authors.initials: SA
authors.lastname: Seidel
authors.affiliation: Lung Investigation Unit, Queen Elizabeth Hospital Birmingham, Mindelsohn way, Edgbaston, Birmingham B15 2WB, UK.
authors.forename: R A
authors.initials: RA
authors.lastname: Stockley
authors.affiliation: Systems Biophysics and Functional Nanosystems, Ludwig Maximilians University München, Amalienstrasse 54, 80799 Munich, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Braun
authors.affiliation: Comprehensive Pneumology Center, Institute of Lung Biology and Disease (iLBD), University Hospital, Ludwig Maximilians University and Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Max-Lebsche-Platz 31, 81377 Munich, Germany.|Max-Planck-Institute of Neurobiology, Am Klopferspitz 18, D-82152 Martinsried, Germany.
authors.forename: D E
authors.initials: DE
authors.lastname: Jenne
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods* / Q000592:standards; D020134:Catalytic Domain; D057809:HEK293 Cells; D006801:Humans; D019272:Leukocyte Elastase / Q000097:blood* / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D012680:Sensitivity and Specificity; D000515:alpha 1-Antitrypsin / Q000097:blood* / Q000737:chemistry / Q000378:metabolism
chemical_list: D000515:alpha 1-Antitrypsin; D019272:Leukocyte Elastase