A new procedure for the preparation of highly active melonin from the dry seeds of Cucumis melo L.
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.
Rojo
M A
MA
Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Valladolid, Spain.
Arias
F J
FJ
Ferreras
J M
JM
Iglesias
R
R
Muñoz
R
R
Citores
L
L
Jimenez
P
P
Girbés
T
T
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
D010940:Plant Proteins; D011500:Protein Synthesis Inhibitors; C079388:melonin protein, Cucumis melo L.; D012260:Ribonucleases