title: Purification and characterization of Moschatin, a novel type I ribosome-inactivating protein from the mature seeds of pumpkin (Cucurbita moschata), and preparation of its immunotoxin against human melanoma cells.
abstract: A novel ribosome-inactivating protein designated Moschatin from the mature seeds of pumpkin (Cucurbita moschata) has been successively purified to homogeneity, using ammonium sulfate precipitation, CM-cellulose 52 column chromatography, Blue Sepharose CL-6B Affinity column chromatography and FPLC size-exclusion column chromatography. Moschatin is a type 1 RIP with a pI of 9.4 and molecular weight of approximately 29 kD. It is a rRNA N-glycosidase and potently blocked the protein synthesis in the rabbit reticulocyte lysate with a IC50 of 0.26 nM. Using the anti-human melanoma McAb Ng76, a novel immunotoxin Moschatin-Ng76 was prepared successfully and it efficiently inhibited the growth of targeted melanoma cells M21 with a IC50 of 0.04 nM, 1500 times lower than that of free Moschatin. The results implied that Moschatin could be used as a new potential anticancer agent.
authors.affiliation: Key Laboratory of Proteomics, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Heng Chuan
authors.initials: HC
authors.lastname: Xia
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Zu Chuan
authors.initials: ZC
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D045744:Cell Line, Tumor; D028464:Cucurbita / Q000737:chemistry*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D000922:Immunotoxins / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification / Q000494:pharmacology*; D008545:Melanoma / Q000188:drug therapy*; D008970:Molecular Weight; D009699:N-Glycosyl Hydrolases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology*; D011817:Rabbits; D054788:Ribosome Inactivating Proteins; D012270:Ribosomes / Q000187:drug effects; D012639:Seeds / Q000737:chemistry*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D007074:Immunoglobulin G; D000922:Immunotoxins; D009699:N-Glycosyl Hydrolases; D054788:Ribosome Inactivating Proteins