title: Methods for 20S Immunoproteasome and 20S Constitutive Proteasome Determination Based on SPRI Biosensors.
abstract: The 20S proteasome, released into the circulation, is a novel cancer biomarker. It exists in two forms: the constitutive proteasome (20Sc) and the immunoproteasome (20Si), which both have separate diagnostic significance. The aim of this work was to develop new methods for 20Si and 20Sc determination. Five alternative specific biosensors usable with the surface plasmon resonance imaging (SPRI) technique for 20Si determination have been developed. Specific 20Si entrapment on the biosensor surface from an analyzed solution was achieved by means of an immobilized specific 20Si receptor. Four of the biosensors contain newly synthesized specific 20Si receptors, while the fifth contains the inhibitor ONX 0914. A method for 20Sc determination using an SPRI biosensor containing PSI inhibitor has been developed. By the introduction of an inhibitor blocking 20Si, 20Sc is selectively determined. All of the methods developed for 20Si and 20Sc determination exhibit good selectivity and satisfactory precision, recoveries and dynamic response ranges. 20Si and 20Sc were determined in blood plasma samples from healthy donors and patients with acute leukemia. In the case of these patients 20Si was the major component, and its level was more than one order of magnitude higher than in the healthy donors.
authors.affiliation: Department of Electrochemistry, Institute of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Sankiewicz
authors.affiliation: Department of Organic Chemistry, Medical University of Bialystok, Kilinskiego 1, 15-089 Bialystok, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Markowska
authors.affiliation: Faculty of Chemical Technology, Poznan University of Technology, pl. Sklodowskiej-Curie 5, 60-965 Poznan, Poland.
authors.forename: Zenon
authors.initials: Z
authors.lastname: Lukaszewski
authors.affiliation: Department of Electrochemistry, Institute of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Puzan
authors.affiliation: Department of Electrochemistry, Institute of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Gorodkiewicz
keywords: 20S proteasome; ONX 0914; PSI; Proteasome inhibitors; Sensor; Surface plasmone resonance imaging