title: [Purification and partial characterization of luffin P1, a peptide with translational inhibitory activity and trypsin inhibitory activity, from seeds of Luffa cylindrica].
abstract: A peptide, luffin P1, from seeds of Luffa cylindrica, was purified by ammonia sulfate precipitation, CM-52 ion exchange chromatography, Blue-gel affinity chromatography and FPLC Mono S ion exchange chromatography. Its molecular weight was 5226.5 as determined by MALDI-TOF-MS analysis. The sequence of N-terminal 11 amino acids of luffin P1 was identical with the partial N-terminal sequence (from G3 to R13) of 6.5K Arg/Glu rich peptide, which was also isolated from the seeds of Luffa cylindrica. Besides, luffin P1 had a very high homology with a trypsin inhibitor, named C2 peptide, from pumpkin seeds. Interestingly, the purified luffin P1 not only showed a strong inhibitory activity on protein synthesis in rabbit reticulocyte lysate cell-free translation system with IC(50) of 0.6 nmol/L, but also had trypsin inhibitory activity with IC(50) of 22 micromol/L.
authors.affiliation: Key Laboratory of Proteomics  Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Hen-Chuan
authors.initials: HC
authors.lastname: Xia
authors.forename: Xin-Xiu
authors.initials: XX
authors.lastname: Yang
authors.forename: Wei-Guo
authors.initials: WG
authors.lastname: Hu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Zu-Chuan
authors.initials: ZC
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001483:Base Sequence; D002852:Chromatography, Ion Exchange / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D029776:Luffa / Q000737:chemistry*; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D014176:Protein Biosynthesis / Q000187:drug effects; D011817:Rabbits; D051381:Rats; D012639:Seeds / Q000737:chemistry*; D020539:Sequence Analysis, Protein; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014361:Trypsin Inhibitors / Q000494:pharmacology
chemical_list: D010940:Plant Proteins; D014361:Trypsin Inhibitors