title: Synthesis and binding studies of Alzheimer ligands on solid support.
abstract: Aminopyrazole derivatives constitute the first class of nonpeptidic rationally designed beta-sheet ligands. Here we describe a double solid-phase protocol for both synthesis and affinity testing. The presented solid-phase synthesis of four types of hybrid compounds relies on the Fmoc strategy and circumvents subsequent HPLC purification by precipitating the final product from organic solution in pure form. Hexa- and octapeptide pendants with internal di- and tetrapeptide bridges are now amenable in high yields to combinatorial synthesis of compound libraries for high-throughput screening purposes. Solid-phase peptide synthesis (SPPS) on an acid-resistant PAM allows us, after PMB deprotection, to subject the free aminopyrazole binding sites in an immobilized state to on-bead assays with fluorescence-labeled peptides. From the fluorescence emission intensity decrease, individual binding constants can be calculated via reference curves by simple application of the law of mass action. Gratifyingly, host/guest complexation can be monitored quantitatively even for those ligands, which are almost insoluble in water.
authors.affiliation: Fachbereich Chemie, Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Rzepecki
authors.forename: Nina
authors.initials: N
authors.lastname: Geib
authors.forename: Manuel
authors.initials: M
authors.lastname: Peifer
authors.forename: Frank
authors.initials: F
authors.lastname: Biesemeier
authors.forename: Thomas
authors.initials: T
authors.lastname: Schrader
mesh_terms: D000544:Alzheimer Disease; D000586:Amination; D016229:Amyloid beta-Peptides / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D008024:Ligands; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D011720:Pyrazoles / Q000138:chemical synthesis / Q000737:chemistry; D012996:Solutions
chemical_list: D016229:Amyloid beta-Peptides; D008024:Ligands; D010455:Peptides; D011720:Pyrazoles; D012996:Solutions; C031280:pyrazole