吡咯喹啉醌生物合成研究进展

吡咯喹啉醌(PQQ)是一种较新近发现的氧化还原酶的辅酶,对微生物及动植物均具有重要生理作用。已知能产生PQQ的生物仅限于某些革兰阴性细菌,已分离得到几种不同来源的PQQ生物合成基因,其序列具有一定的保守性。PQQ的生物合成涉及4～7个基因,这些基因一般成簇排列。业已证明,谷氨酸和酪氨酸是PQQ合成的前体物质。对各个基因的功能已有不同程度的了解,但PQQ的生物合成途径还尚未阐明。     

吡咯喹啉醌研究进展

吡咯喹啉醌（PQQ）是继烟酰胺和黄素核苷酸之后发现的氧化还原酶的第3种辅酶,具有多种生理功能,在食品、医药及农业等行业有广泛的应用前景。我们简要综述了PQQ参与醌酶电子传递、增强微生物对极端环境的适应能力、促进植物生长、刺激神经生长因子生成等生物学功能及相关作用机制,介绍了PQQ生产菌、PQQ合成基因及PQQ生物合成的调控等方面的研究进展。     

吡咯喹啉醌及其生理功能

吡咯喹啉醌（ＰＱＱ）──一种新的氧化还原酶辅基,存在于一些微生物、植物和动物组织中,参与催化生物体内氧化还原反应。研究表明ＰＱＱ具有一些重要生理功能：刺激某些植物发育及微生物和人体细胞生长;作为动物体生长发育的必需因子;清除自由基保护机体免受自由基损害;防治肝损伤;促进神经生长因子合成等。因此,ＰＱＱ具有一定的医药应用前景。     

吡咯喹啉醌生理医学功效研究进展

吡咯喹啉醌(PQQ)是一种小分子醌类化合物,由某些细菌合成作为细菌脱氢酶氧化还原反应的辅助因子,并广泛存在于各种生物组织中。综述了其在生理医学功效方面的研究进展情况,分析其在神经退行性疾病、心脏病、解毒、消炎、抗癌、预防白内障及骨代谢疾病等方面的临床应用潜力,并对其未来在水生生物生理生态学领域的研究方向进行了展望。     

重组酶法定量分析吡咯喹啉醌

用ＤＥＡＥ－ｓｅｐｈａｃｅｌ和ＣＭ－ｃｅｌｕｌｏｓｅ柱层析的方法从Ｃｏｍａｍｏｎａｓｔｅｓｔｏｓｔｅｒｏｎｉ菌体中纯化得到一定纯度的脱辅基的乙醇脱氢酶。在含３ｍＭＣａＣｌ２的Ｔｒｉｓ／ＨＣｌ缓冲液（２０ｍＭ,ｐＨ７．０）中,该酶能与ＰＱＱ重组成有活性的全酶,测出的全酶活性大小与外加ＰＱＱ的量成正比,从而定量分析ＰＱＱ。该法专一、灵敏、可靠。     

吡咯喹啉醌生物合成研究进展

吡咯喹啉醌(pyrroloquinoline quinone,PQQ)是一种多肽修饰类天然产物,是继烟酰胺和核黄素之后第三类辅酶,具有抗氧化、抗衰老、提高免疫力等重要生理功能,在医药、保健等领域具有重要价值.目前,PQQ的大规模制备仍然存在诸多问题,限制了PQQ的广泛应用.当前迫切需求低成本的合成方式,以充分实现其广阔...     

高效液相色谱法分析吡咯喹啉醌

目的:建立一种通过高效液相色谱(HPLC)定量测定吡咯喹啉醌(PQQ)的分析方法。方法:将PQQ标准品及发酵制备的PQQ结晶粉末溶于10 mmol/L Na OH溶液,利用高效液相色谱仪进行测定。采用Waters XBridge C18(4.6 mm×150 mm,5μm)作为分离柱,用甲醇-水(用三氟乙酸调节p H值为1.0)梯度洗脱,流速为1.0 m L/min,于室温下检测PQQ,检测波长为365.8 nm。结果:检测得PQQ标准品的保留时间约为7.8 min,在0.031 25~1 mg/m L范围内线性关系良好,相关系数(r2)在0.9999以上,平均回收率为98.6%。结论:高效液相色谱法分析PQQ的灵敏度和准确度高,是一种可靠的PQQ定量分析方法。     

吡咯喹啉醌（PQQ）的研究进展

吡咯喹啉醌是一种与烟酰胺核苷酸、黄素核苷酸不同的新型辅基.近年来,荷兰、日本等学者对它进行了初步研究,而国内研究起步较晚,文章综述了吡咯喹啉醌的发现、分离纯化、鉴定、理化性质以及生理功能,这有利于进一步研究吡咯喹啉醌的分布、产生机理、生物学性质、生理功能及其应用.这将对促进酶学学科的发展具有重要的理论和实践意义.     

吡咯喹啉醌(PQQ)营养作用研究进展

吡咯喹啉醌(PQQ)是细菌脱氢酶氧化还原反应的辅助因子,广泛存在于微生物、植物、动物及人体中。迄今为止,PQQ催化氧化还原反应的能力远超过已知的生物活性分子。体内外研究表明,PQQ能够刺激微生物生长,增强其对极端环境的适应能力,并对植物和动物的生长、发育和繁殖十分重要。本文阐述了PQQ的理化性质、自然分布和营养作用的研究进展,以推动其在食品、医疗及农林渔业领域的发展应用。     

甲醇利用型吡咯喹啉醌产生菌的筛选及鉴定

从虎杖内生细菌和黏细菌中筛选吡咯喹啉醌(PQQ)产生菌。采用3种以甲醇为唯一碳源的培养基对160株供试菌株进行摇瓶培养发酵,发酵产物采用光谱学分析法及HPLC法筛选。结果显示,通过初筛和复筛共得到甲醇利用型菌134株,PQQ产生菌4株,其中菌株083114的PQQ产量为64.34 mg/L。菌株083114的16S rRNA基因序列分析结果显示,其序列与酸快生芽孢杆菌(Bacillus acidiceler)的系统发育关系最近。虎杖内生细菌及黏细菌中存在PQQ产生菌。     

新辅基吡咯喹啉醌(PQQ)生物合成基因研究进展

吡咯喹啉醌（Ｐｙｒｏｌｏｑｕｉｎｏｌｉｎｅ－Ｑｕｉｎｏｎｅ,ＰＱＱ）是氧化还原酶的新辅基。它在细菌体内是由一组排列成簇的相关基因即ｐｑｑ基因控制合成的。根据不同细菌来源ｐｑｑ基因的同源性和对应关系,可将ｐｑｑ基因归为７类：簇基因１～７。在Ａｃｉｎｅｔｏｂａｃｔｅｒｃａｌｃｏａｃｅｔｉｃｕｓ中存在其中四个,ＫｌｅｂｓｉｅｌａＰｎｅｕｍｏｎｉａｅ和ＭｅｔｈｙｌｏｂａｃｔｅｒｉｕｍＯｒｇａｎｏｐｈｉｌｕｍＤＳＭ７６０中６个,而Ｍｅｔｈｙｌｏｂａｃｔｅｒｉｕｍｅｘ－ｔｏｒｑｕｅｎｓＡＭ１中存在全部７个簇基因。簇基因１编码一个由２２～２９年氨基酸组成的小肽,此小肽可能是ＰＱＱ的前体,簇基因２可能涉及ＰＱＱ跨膜转运,簇基因３可能负责ＰＱＱ合成的最后一步酶催化,簇基因５可能涉及ＰＱＱ合成中某种酶的辅因子合成,簇基因６和７可能负责小肽的加工。簇基因４功能还不清楚,但在Ｍ．ｅｘｔｏｒｑｕｅｎｓＡＭ１中簇基因３和４是以融合基因存在的。     

Pyrroloquinoline Quinone is a Potent Neuroprotective Nutrient Against 6-Hydroxydopamine-Induced Neurotoxicity

Pyrroloquinoline quinone (PQQ), which is an essential nutrient, has been shown to act as an antioxidant. Reactive oxygen species (ROS) are thought to be responsible for neurotoxicity caused by the neurotoxin 6-hydroxydopamine (6-OHDA). In this study, we investigated the ability of PQQ to protect against 6-OHDA-induced neurotoxicity using human neuroblastoma SH-SY5Y. When SH-SY5Y cells were exposed to 6-OHDA in the presence of PQQ, PQQ prevented 6-OHDA-induced cell death and DNA fragmentation. Flow cytometry analysis using the ROS-sensitive fluorescence probe, dihydroethidium, revealed that PQQ reduced elevation of 6-OHDA-induced intracellular ROS. In contrast to PQQ, antioxidant vitamins, ascorbic acid and α-tocopherol, had no protective effect. Moreover, we showed that PQQ effectively scavenged superoxide, compared to the antioxidant vitamins. Therefore, our results suggest the protective effect of PQQ on 6-OHDA-induced neurotoxicity is involved, at least in part, in its function as a scavenger of ROS, especially superoxide.     

Pyrroloquinoline quinone (PQQ) is reduced to pyrroloquinoline quinol (PQQH2) by vitamin C,and PQQH2 produced is recycled to PQQ by air oxidation in buffer solution at pH 7.4

Measurements of the reaction of sodium salt of pyrroloquinoline quinone (PQQNa₂) with vitamin C (Vit C) were performed in phosphate-buffered solution (pH 7.4) at 25 °C under nitrogen atmosphere, using UV–vis spectrophotometry. The absorption spectrum of PQQNa₂ decreased in intensity due to the reaction with Vit C and was changed to that of pyrroloquinoline quinol (PQQH₂, a reduced form of PQQ). One molecule of PQQ was reduced by two molecules of Vit C producing a molecule of PQQH₂ in the buffer solution. PQQH₂, thus produced, was recycled to PQQ due to air oxidation. PQQ and Vit C coexist in many biological systems, such as vegetables, fruits, as well as in human tissues. The results obtained suggest that PQQ is reduced by Vit C and functions as an antioxidant in biological systems, because it has been reported that PQQH₂ shows very high free-radical scavenging and singlet-oxygen quenching activities in buffer solutions.     

醌还原酶法进行芥蓝抗癌活性的快速检测

研究了不同提取方法,不同细胞裂解剂和醌还原酶(QR)反应液的培育时间对QR法分析的影响。结果表明,芥蓝组织用磷酸缓冲液(5mmol/LK2HPO4-KH2PO4,1mmol/LEDTA,pH7.6)提取效果良好,与常用的三元试剂提取法效果相当。这种方法简单而有效,优于其他有机溶剂提取法。0.4%乙基苯基聚乙二醇(NP40)可以替代细胞裂解剂——0.8%毛地黄皂苷用于QR分析,且效果良好,QR反应中反应液的培育时间以5￣10min为宜。     

Immunological evidence for two types of PQQ-dependent d-glucose dehydrogenase in bacterial membranes and the location of the enzyme in Escherichia coli

Abstract Using an antibody raised against d -glucose dehydrogenase (EC 1.1.99.17) purified from Pseudomonas fluorescens , immuno-cross-reactivity with the enzymes from several bacterial strains and localization of the enzyme in Escherichia coli were examined. The antibody cross-reacted with glucose dehydrogenases from various Gram-negative bacteria examined. As a result, it became apparent that the enzymes from Gluconobacter, Acetobacter, Pseudomonas and Acinetobacter , which existed as holoenzymes in the membranes, had lower molecular weights than those from E. coli and Klebsiella , which were apoenzymes.
Treatment with trypsin of right-side out and inside-out membrane vesicles from E. coli clearly demonstrated that d -glucose dehydrogenase was located on the outer surface of the cytoplasmic membrane of E. coli , as had been suggested for Pseudomonas .     

PqqD Is a Novel Peptide Chaperone That Forms a Ternary Complex with the Radical S-Adenosylmethionine Protein PqqE in the Pyrroloquinoline Quinone Biosynthetic Pathway

Pyrroloquinoline quinone (PQQ) is a product of a ribosomally synthesized and post-translationally modified pathway consisting of five conserved genes, pqqA-E. PqqE is a radical S-adenosylmethionine (RS) protein with a C-terminal SPASM domain, and is proposed to catalyze the formation of a carbon-carbon bond between the glutamate and tyrosine side chains of the peptide substrate PqqA. PqqD is a 10-kDa protein with an unknown function, but is essential for PQQ production. Recently, in Klebsiella pneumoniae (Kp), PqqD and PqqE were shown to interact; however, the stoichiometry and K_D were not obtained. Here, we show that the PqqE and PqqD interaction transcends species, also occurring in Methylobacterium extorquens AM1 (Me). The stoichiometry of the MePqqD and MePqqE interaction is 1:1 and the K_D, determined by surface plasmon resonance spectroscopy (SPR), was found to be ∼12 μm. Moreover, using SPR and isothermal calorimetry techniques, we establish for the first time that MePqqD binds MePqqA tightly (K_D ∼200 nm). The formation of a ternary MePqqA-D-E complex was captured by native mass spectrometry and the K_D for the MePqqAD-MePqqE interaction was found to be ∼5 μm. Finally, using a bioinformatic analysis, we found that PqqD orthologues are associated with the RS-SPASM family of proteins (subtilosin, pyrroloquinoline quinone, anaerobic sulfatase maturating enzyme, and mycofactocin), all of which modify either peptides or proteins. In conclusion, we propose that PqqD is a novel peptide chaperone and that PqqD orthologues may play a similar role in peptide modification pathways that use an RS-SPASM protein.