title: Boletus edulis Nitrite Reductase Reduces Nitrite Content of Pickles and Mitigates Intoxication in Nitrite-intoxicated Mice.
abstract: Pickles are popular in China and exhibits health-promoting effects. However, nitrite produced during fermentation adversely affects health due to formation of methemoglobin and conversion to carcinogenic nitrosamine. Fruiting bodies of the mushroom Boletus edulis were capable of inhibiting nitrite production during pickle fermentation. A 90-kDa nitrite reductase (NiR), demonstrating peptide sequence homology to fungal nitrite reductase, was isolated from B. edulis fruiting bodies. The optimum temperature and pH of the enzyme was 45 °C and 6.8, respectively. B. edulis NiR was capable of prolonging the lifespan of nitrite-intoxicated mice, indicating that it had the action of an antidote. The enzyme could also eliminate nitrite from blood after intragastric administration of sodium nitrite, and after packaging into capsule, this nitrite-eliminating activity could persist for at least 120 minutes thus avoiding immediate gastric degradation. B. edulis NiR represents the first nitrite reductase purified from mushrooms and may facilitate subsequent applications.
authors.affiliation: State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing 100193, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Institute of Biotechnology and Germplasmic Resource, Yunnan Academy of Agricultural Science, Kunming 650223, P.R. China.
authors.forename: Guoting
authors.initials: G
authors.lastname: Tian
authors.affiliation: State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing 100193, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Feng
authors.affiliation: Institute of Biotechnology and Germplasmic Resource, Yunnan Academy of Agricultural Science, Kunming 650223, P.R. China.
authors.forename: Jack Ho
authors.initials: JH
authors.lastname: Wong
authors.affiliation: Institute of Biotechnology and Germplasmic Resource, Yunnan Academy of Agricultural Science, Kunming 650223, P.R. China.
authors.forename: Yongchang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing 100193, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory for Agrobiotechnology and Department of Microbiology, China Agricultural University, Beijing 100193, China.
authors.forename: Hexiang
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
authors.forename: Tzi Bun
authors.initials: TB
authors.lastname: Ng
mesh_terms: D000363:Agaricales / Q000737:chemistry* / Q000201:enzymology; D000818:Animals; D000931:Antidotes / Q000302:isolation & purification / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology*; D002273:Carcinogens / Q000037:antagonists & inhibitors / Q000378:metabolism; D004032:Diet; D057075:Enzyme Assays; D005285:Fermentation / Q000187:drug effects; D048690:Fruiting Bodies, Fungal / Q000737:chemistry / Q000201:enzymology; D005656:Fungal Proteins / Q000302:isolation & purification / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008297:Male; D008706:Methemoglobin / Q000037:antagonists & inhibitors / Q000378:metabolism; D051379:Mice; D009572:Nitrite Reductases / Q000302:isolation & purification / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology*; D009602:Nitrosamines / Q000037:antagonists & inhibitors / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D012977:Sodium Nitrite / Q000378:metabolism / Q000506:poisoning*; D013696:Temperature; D014675:Vegetables / Q000506:poisoning
chemical_list: D000931:Antidotes; D002273:Carcinogens; D005656:Fungal Proteins; D009602:Nitrosamines; D008706:Methemoglobin; D009572:Nitrite Reductases; D012977:Sodium Nitrite