title: A new procedure for the preparation of highly active melonin from the dry seeds of Cucumis melo L.
abstract: Melon (Cucumis melo L.) dry seeds contain melonin, a protein that strongly inhibits ribosomes from different prokaryotic and eukaryotic sources including those from melon. The protein was purified by a new method to yield highly active and stable protein preparations that involves chromatography through S-Sepharose Fast Flow, CM-Sepharose, Superdex 75 and Mono-S. Melonin shows important functional properties: 1) its inhibitory effects on translation were irreversible; 2) it is a single unglycosylated polypeptide chain with an apparent M(r) of 22000; 3) it degrades RNA in a dose-dependent way without affecting DNA. In the light of present results melonin can be considered as a new plant RNase of unusual properties.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Valladolid, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Rojo
authors.forename: F J
authors.initials: FJ
authors.lastname: Arias
authors.forename: J M
authors.initials: JM
authors.lastname: Ferreras
authors.forename: R
authors.initials: R
authors.lastname: Iglesias
authors.forename: R
authors.initials: R
authors.lastname: Muñoz
authors.forename: L
authors.initials: L
authors.lastname: Citores
authors.forename: P
authors.initials: P
authors.lastname: Jimenez
authors.forename: T
authors.initials: T
authors.lastname: Girbés
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004305:Dose-Response Relationship, Drug; D005638:Fruit / Q000737:chemistry*; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008970:Molecular Weight; D010940:Plant Proteins / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D012260:Ribonucleases / Q000302:isolation & purification* / Q000378:metabolism; D012639:Seeds / Q000737:chemistry
chemical_list: D010940:Plant Proteins; D011500:Protein Synthesis Inhibitors; C079388:melonin protein, Cucumis melo L.; D012260:Ribonucleases