磷脂酶D及其催化机制的研究进展北大核心CSCD

磷脂酶D是一类具有水解作用和磷酰基转移作用的酶,故其在磷脂改性方面发挥重要作用。主要对磷脂酶D及其催化机制研究现状进行介绍,包括磷脂酶D的来源与制备、催化合成磷脂质、磷脂酶D的分子结构、分子催化机制与分子改造。最后对磷脂酶D的发展进行了展望。     

磷脂酶D及其催化机制的研究进展

磷脂酶D是一类具有水解作用和磷酰基转移作用的酶,故其在磷脂改性方面发挥重要作用。主要对磷脂酶D及其催化机制研究现状进行介绍,包括磷脂酶D的来源与制备、催化合成磷脂质、磷脂酶D的分子结构、分子催化机制与分子改造。最后对磷脂酶D的发展进行了展望。     

超声波对大豆水化油脚-磷脂酶A2反应体系的影响

大豆磷脂酶改性可以明显改善其O／W乳化性能，磷脂酶改性反应时间一般需要7h，而超声波处理则可明显缩短反应时间。以大豆水化油脚为原料，研究了超声波处理对磷脂酶A2制备酶改性大豆磷脂的影响。结果表明，在pH7．5，55℃反应条件下，采用超声波辅助反应40min后，所制备的溶血磷脂HLB值达到8。与未采用超声波溶血磷脂HLB值相同。超声波促进磷脂酶改性效果明显。     

大豆磷脂改性研究进展

综述了国内外大豆磷脂的改性方法,包括物理、化学和酶法改性。物理改性方法主要包括溶剂分提法、超临界流体萃取法、色谱柱分离法、膜分离法等;化学改性方法主要包括乙酰化法、羟基化法、酰羟化法、氢化法、磺化及磷脂与金属相互作用等;酶法改性中的酶应用最多的是磷脂酶,包括磷脂酶A1、A2、C、D。大豆磷脂通过物理、化学或者酶法改性后,改变了HLB值范围,改善了磷脂的乳化特性,提高了磷脂在水中的分散特性,扩大了磷脂在食品、医药、化妆品、石油等工业方面的应用。     

磷脂酶法改性研究进展

该文简要介绍磷脂化合物分类、结构特点,及不同动物、植物、微生物来源工具酶分子结构和催化性质。酶的种类主要包括磷脂酶A_1、A_2、C、D及脂肪酶。对在非水相体系中,磷脂酶法改性途径,包括水解、醇解、酯化和酯交换反应,及影响反应因素,包括酶的种类、反应体系(包括体系相态和溶剂效应)、底物浓度和水分活度进行阐述。     

大豆溶血磷脂的制备及其生物安全性分析

大豆溶血磷脂是原有大豆磷脂结构中失去一个脂肪酸基团的改性磷脂的统称,较大豆磷脂增强了亲水性和抗氧化性,被广泛地用于医药、食品和畜牧业。采用磷脂酶A1对大豆磷脂进行改性,以水解率和红外光谱检测其改性程度,以溶血试验和细胞毒性试验检测其生物安全性。结果表明:采用磷脂酶A1在60℃、40%大豆磷脂-水的体系中酶解大豆磷脂所制备的大豆溶血磷脂,纯化后为棕色、块状物质且无明显豆腥味;其水解率为101. 6%;大豆溶血磷脂中双键和酰胺键的吸收峰明显低于大豆磷脂;大豆溶血磷脂和大豆磷脂均有溶血现象,且二者在200μg/mL以下溶血率均低于5%,视为生物安全;大豆溶血磷脂在20μg/mL、大豆磷脂在50μg/mL以下时,Caco-2细胞的存活率均高于80%。综上,采用磷脂酶A1制备的大豆溶血磷脂,在一定质量浓度下使用,具备生物安全性。     

微生物磷脂酶D的克隆表达研究进展

磷脂酶D（Phospholipase D, PLD, EC 3.1.4.4）是催化磷脂的磷酸二酯键水解和转磷脂酰基反应的一类酶的总称。PLD所具有的转磷脂活性使其在食品、医药以及细胞生物学等领域具有广泛的应用价值,但其大规模工业化生产受到诸多因素的限制。利用基因工程技术对磷脂酶D基因进行克隆表达,开发高产量、高纯度和高转磷脂活性的PLD资源成为当前的研究热点。本文主要对微生物PLD克隆与高效表达方面的研究进展进行分析,以期对微生物PLD的大规模生产及其相关产品的开发利用提供参考。     

磷脂酶D特性及其在磷脂酰丝氨酸合成中的应用

磷脂酰丝氨酸（Phosphatidylserine，PS）是一种新资源食品，在自然界中含量稀少，提取困难。磷脂酶D（Phospholipase D，PLD）是生物酶法制备磷脂酰丝氨酸的关键合成酶。本文主要介绍了PLD的分子结构特点、催化机理及酶活特性，并总结了目前PS的制备方法，重点对PLD酶催化制备磷脂酰丝氨酸的研究进展及反应体系进行了论述，并对催化制备PS反应体系的选择进行了分析和展望，以期为深化酶法技术制备PS的研究提供参考，以此推动新资源食品PS的工业化生产和应用。     

大豆磷脂的酶法改性研究进展

大豆磷脂的酶改性是目前各类改性方法中的研究热点,论述了磷脂酶A1、A2、B、C、D,脂肪酶,神经磷脂酶的特性、作用机理及其在大豆磷脂改性中的应用。本文认为,酶改性是今后大豆磷脂深加工的发展方向,如能提高酶的活性、稳定性和选择性,解决磷脂酶生产的一些问题,酶改性方法将会有广泛的发展前景。     

贫水相磷脂改性及改性产品性能的研究

以大豆浓缩磷脂为底物,探讨了贫水相中磷脂酶A1改性大豆浓缩磷脂的可行性。利用单因素实验确定了最佳反应条件,同时对产品的乳化性能进行了研究。实验获得的最佳反应条件为:反应温度50℃,加酶量500μg/g,初始pH 6,反应时间12 h,底物大豆浓缩磷脂质量分数75%。在此条件下所得改性产品的HLB值为10。     

磷脂改性方法的研究进展(Ⅰ)——物理与化学改性

磷脂通过物理或化学方法改性,可以改变磷脂的HLB值范围,扩大磷脂在工业上的应用范围。综述了国内外磷脂物理和化学改性方法研究的进展。物理改性方法主要包括溶剂分提法、超临界CO2萃取法、膜分离法、有机溶剂沉淀法、金属离子沉淀法、色谱柱分离法、微胶囊法等。化学改性方法主要包括酸碱水解法、乙酰化法、羟基化法、羟酰化法、氢化法、磺化法、乙氧基改性法等。     

磷脂改性方法的研究进展(Ⅱ)——酶改性

综述了国内外磷脂的酶改性方法的研究进展。酶改性具有反应物不需纯化,反应条件温和,速度快、进行完全、副产物少、酶制剂作用部位准确、来源方便等优点。磷脂经酶改性后,改变了HLB值的范围,拓宽了磷脂在工业上的应用范围。     

Enzymes as biocatalysts in the modification of natural lipids

Though designed by nature to effect hydrolysis of lipids, lipases can, under appropriate reaction conditions, promote ester formation through reaction of acids and alcohols (esterification) or of esters with acids (acidolysis), alcohols (alcoholysis), or other esters (interesterification). Compared with chemical processes already carried out on an industrial scale enzymic reactions occur under milder (and ‘greener’) conditions though they may take longer. Of greater significance is the specificity shown by the enzymes which permits the formation of lipid derivatives not easily prepared by conventional laboratory procedures. This review describes the lipases and their various specificities and reports on their use in hydrolysis and in the production of phospholipids, fatty acids, alkyl esters, mono- and di-acylglycerols, triacylglycerols, other esters, and amides. Some of these have already led to marketable products but for the most part the full potential of these reactions has yet to be realised. The reactions of other enzymes promoting interesting reactions at unsaturated centres are also described. © 1999 Society of Chemical Industry     

酶固定化研究进展

由于酶催化的特异性、高效性和温和性,酶的工业化利用一直是酶工程领域的研究热点。酶固定化是酶工程发展的必然趋势。固定化酶已在众多工业生产中发挥越来越重要的作用,围绕酶固定的载体材料开发与固定技术研究进展很快。传统酶固定化主要包括吸附、包埋、结合或化学交联等技术,然而固定化酶的稳定性、牢固性及催化效率等与工业实际应用仍具有很大差距。近年来,随着纳米技术、高分子材料化学、表面化学、蛋白质结构分析及分子生物学等学科的快速发展,新型载体材料和固定化技术不断涌现。以纳米载体材料、纳米磁性材料、金属有机骨架复合材料为代表的新型固定载体以及以定向化学修饰研究为代表的固定化技术取得了显著进展。本文重点对酶固定的纳米载体、金属有机骨架材料以及定向修饰固定技术进行了简要综述,同时对研究前景作了简要展望。     

Sono-activation of food enzymes: From principles to practice

Over the last decade, sono-activation of enzymes as an emerging research area has received considerable attention from food researchers. This kind of relatively new application of ultrasound has demonstrated promising potential in facilitating the modern food industry by broadening the application of various food enzymes, improving relevant industrial unit operation and productivity, as well as increasing the yield of target products. This review aims to provide insight into the fundamental principles and possible industrialization strategies of the sono-activation of food enzymes to facilitate its commercialization. This review first provides an overview of ultrasound application in the activation of food protease, carbohydrase, and lipase. Then, the recent development on ultrasound activation of food enzymes is discussed on aspects including mechanisms, influencing factors, modification effects, and its applications in real food systems for free and immobilized enzymes. Despite the far fewer studies on sono-activation of immobilized enzymes compared with those on free enzymes, we endeavored to summarize the relevant aspects in three stages: ultrasound pretreatment of free enzyme/carrier, assistance in immobilization process, and modification of the already immobilized enzyme. Lastly, challenges for the scalability of ultrasound in these target areas are discussed and future research prospects are proposed.     

酶在植物多糖研究中的应用进展

植物多糖是植物生命活动所必需的生物大分子,其研究主要集中在提取分离、结构修饰、结构解析及生物活性等方面。酶作为常见的生物催化剂,因其高效、专一的特性,在植物多糖研究中的应用也越来越广泛。该文概述植物中淀粉、纤维素、果胶、半纤维素等多糖的结构信息,并介绍淀粉酶、纤维素酶、果胶酶、半纤维素酶等的分类和作用方式;总结酶在植物多糖提取、结构修饰及在结构分析中的应用研究进展,以期深化对酶、植物多糖的理解以及开发多糖在食品、生物医药和其他领域的应用。     

Properties of Calanus finmarchicus biomass during frozen storage after heat inactivation of autolytic enzymes

Calanus finmarchicus is a marine zooplankton of interest for the aquaculture industry, as well as for nutraceuticals and the cosmetic industry. The chemical composition of C. finmarchicus rapidly changes postmortem due to autolytic processes; in particular phospholipids rapidly degrade to give free fatty acids. The aim of this study was to inactivate autolytic enzymes in C. finmarchicus by applying heat (72 °C, 5-30 min) through mixing with boiling, fresh water, and further to explore the effects of heat (70 °C, 15 min) combined with long time storage (−20 °C, 12 months) of treated and untreated material. Heat treatment (5 min) inactivated all tested enzymes and maintained the initial amount of phospholipids, total lipids and crude protein. Storage of untreated material led to complete degradation of all phospholipids, whereas heat treatment resulted in a stable product containing the initial amount of phospholipids and astaxanthin.     

Halophilic hydrolases as a new tool for the biotechnological industries

Halophilic micro‐organisms are able to survive in high salt concentrations because they have developed diverse biochemical, structural and physiological modifications, allowing the catalytic synthesis of proteins with interesting physicochemical and structural properties. The main characteristic of halophilic enzymes that allows them to be considered as a novel alternative for use in the biotechnological industries is their polyextremophilicity, i.e. they have the capacity to be thermostable, tolerate a wide range of pH, withstand denaturation and tolerate high salt concentrations. However, there have been relatively few studies on halophilic enzymes, with some being based on their isolation and others on their characterisation. These enzymes are scarcely researched because attention has been focused on other extremophile micro‐organisms. Only a few industrial applications of halophilic enzymes, principally in the fermented food, textile, pharmaceutical and leather industries, have been reported. However, it is important to investigate applications of these enzymes in more biotechnological processes at both the chemical and the molecular level. This review discusses the modifications of these enzymes, their industrial applications and research perspectives in different biotechnological areas. Copyright © 2012 Society of Chemical Industry