title: Substance P inactivating enzymes in human cerebrospinal fluid.
abstract: The Km and Vmax values were determined for enzymes in human lumbar cerebrospinal fluid (CSF) that inactivate synthetic substance P (SP = RPKPQQFFGLM-NH2) and produce metabolic products. For the human lumbar CSF samples analyzed in this study, Km = 2.24 +/- 0.93 mM and Vmax = 0.113 +/- 0.035 nmol/ml/min (n = 10; mean +/- SEM) for the rate of decrease of SP. HPLC analysis of the incubated synthetic peptide fragments demonstrated that the primary enzymatically produced fragment is SP(3-11), with minor amounts in decreasing order of SP(1-4), SP(1-7), and SP(1-9). Electrospray ionization mass spectrometry (ESI-MS) confirmed the appropriate molecular weights for the four peptides, SP(3-11), SP(1-4), SP(1-7), and SP(1-9). These data demonstrate that the primary enzyme in human lumbar CSF that acts on synthetic SP is a post-proline cleaving enzyme (PPCE).
authors.affiliation: Charles B. Stout Neuroscience Mass Spectrometry Laboratory, University of Tennessee, Memphis 38163.
authors.forename: T
authors.initials: T
authors.lastname: Kaneko
authors.forename: G
authors.initials: G
authors.lastname: Wood
authors.forename: W L
authors.initials: WL
authors.lastname: Crouch
authors.forename: D M
authors.initials: DM
authors.lastname: Desiderio
mesh_terms: D000595:Amino Acid Sequence; D004798:Enzymes / Q000134:cerebrospinal fluid*; D006801:Humans; D008161:Lumbosacral Region; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D013373:Substance P / Q000037:antagonists & inhibitors*
chemical_list: D004798:Enzymes; D013373:Substance P