title: Identification of bikunin as an endogenous inhibitor of dynorphin convertase in human cerebrospinal fluid.
abstract: Dynorphin-converting enzymes constitute a group of peptidases capable of converting dynorphins to enkephalins. Through the action of these enzymes, the dynorphin-related peptides bind to delta-opioid instead of kappa-opioid receptors, leading to a change in the biological function of the neuropeptides. In this article, we describe the identification of the protein bikunin as an endogenous, competitive inhibitor of a dynorphin-converting enzyme in human cerebrospinal fluid. This protein is present together with its target enzyme in the same body fluids. The K(M) value of the convertase was found to be 9 microm, and the K(i) value of the inhibitor was 1.7 nm. The finding indicates that bikunin may play a significant role as a regulatory mechanism of neuropeptides, where one bioactive peptide is converted to a shorter sequence, which in turn, can affect the action of its longer form.
authors.affiliation: Department of Neurobiochemistry, Faculty of Chemistry and Regional Laboratory, Jagiellonian University, Krakow, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Suder
authors.forename: Anna
authors.initials: A
authors.lastname: Bierczynska-Krzysik
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kraj
authors.forename: Peter
authors.initials: P
authors.lastname: Brostedt
authors.forename: Pawel
authors.initials: P
authors.lastname: Mak
authors.forename: Maciej
authors.initials: M
authors.lastname: Stawikowski
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Rolka
authors.forename: Fred
authors.initials: F
authors.lastname: Nyberg
authors.forename: Erik
authors.initials: E
authors.lastname: Fries
authors.forename: Jerzy
authors.initials: J
authors.lastname: Silberring
mesh_terms: D000510:Alpha-Globulins / Q000134:cerebrospinal fluid* / Q000302:isolation & purification / Q000502:physiology*; D000595:Amino Acid Sequence; D002556:Cerebrospinal Fluid Proteins / Q000302:isolation & purification / Q000502:physiology; D003546:Cysteine Endopeptidases / Q000134:cerebrospinal fluid*; D015853:Cysteine Proteinase Inhibitors / Q000134:cerebrospinal fluid / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data
chemical_list: D000510:Alpha-Globulins; D002556:Cerebrospinal Fluid Proteins; D015853:Cysteine Proteinase Inhibitors; C016001:alpha-1-microglobulin; D003546:Cysteine Endopeptidases; C063078:dynorphin converting enzyme