title: Isolation of a ribonuclease with antiproliferative and HIV-1 reverse transcriptase inhibitory activities from Japanese large brown buckwheat seeds.
abstract: A ribonuclease, with a molecular mass of 22.5 kDa and an N-terminal sequence exhibiting resemblance to previously isolated buckwheat storage proteins and allergens, was isolated from Japanese large brown buckwheat seeds. The ribonuclease was purified using a simple protocol that comprised ion exchange chromatography on Q-Sepharose and DEAE-cellulose and gel filtration on Superdex 75. The ribonuclease exhibited low activity toward poly U, lower activity toward poly C, and very low activity toward poly A and poly G. The enzyme was activated upon exposure to 10 mM of Fe(2+) and Zn(2+) ions but was inhibited by Ca(2+), Mg(2+), and Mn(2+) ions at the same concentration. The optimum pH and optimum temperature for the enzyme were pH 9 and 60 °C, respectively. It inhibited proliferation of HepG2 hepatoma and MCF 7 breast cancer cells, with an IC50 value of 79.2 and 63.8 μM, respectively. It potently inhibited HIV-1 reverse transcriptase activity with an IC50 of 48 μM. However, there were no antifungal and mitogenic activities.
authors.affiliation: Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.
authors.forename: Susu
authors.initials: S
authors.lastname: Yuan
authors.forename: Juan
authors.initials: J
authors.lastname: Yan
authors.forename: Xiujuan
authors.initials: X
authors.lastname: Ye
authors.forename: Zujian
authors.initials: Z
authors.lastname: Wu
authors.forename: Tzibun
authors.initials: T
authors.lastname: Ng
mesh_terms: D000595:Amino Acid Sequence; D045744:Cell Line, Tumor; D004789:Enzyme Activation; D004795:Enzyme Stability; D019612:Fagopyrum / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D012260:Ribonucleases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry / Q000201:enzymology / Q000235:genetics
chemical_list: D010940:Plant Proteins; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase; D012260:Ribonucleases