卡拉胶酶的研究进展

卡拉胶酶主要有κ－卡拉胶酶,ι－卡拉胶酶,λ－卡拉胶酶,是水解酶的一种。本文从酶的分类和来源,底物专一性和作用方式,酶的性质,产酶菌株及酶系,酶的应用五个方面综述了卡拉胶酶的研究进展。     

琼胶酶研究进展*

琼胶酶是一种多糖水解酶,根据降解琼脂糖的作用方式不同,可以分为α-琼胶酶（EC3.2.1.-）和β-琼胶酶（EC3.2.1.81）。中从琼胶酶的分类及酶活测定,酶的来源,产酶微生物的酶系及酶学性质,琼胶酶的分子生物学研究,酶的应用几个方面综述了琼胶酶的研究进展。     

甘蔗渣固体发酵亮菌产纤维素和木质素降解酶的测定

探索亮菌甘蔗渣固体发酵产纤维素和木质素降解酶的能力,对甘蔗渣的充分利用,以及开发新的、高效的产纤维素降解酶和木质素降解酶的微生物资源极为重要。本研究用专一的底物分别对亮菌分泌的外切葡聚糖酶、内切葡聚糖酶、β-葡萄糖苷酶、锰过氧化酶、漆酶和木质素过氧化物酶的酶活力进行测定。结果显示亮菌固态发酵可以分泌外切葡聚糖酶、内切葡聚糖酶、木质素过氧化物酶和漆酶。其酶活力随着时间的延长而增长,达到最高峰值后,开始下降。其中,漆酶酶活力最高,第55天达到最大值为(2 336±183)U/g。各种酶的最高酶活力峰值出现时间不尽相同,体现出多种酶之间很好的协同作用。因此,亮菌甘蔗渣固体发酵具有分泌纤维素和木质素降解酶的能力,尤其产具有高酶活力的漆酶,具有潜在的工业化应用前景。     

真菌漆酶的酶活测定方法评价

目前真菌漆酶酶活的测定方法多样,没有统一的标准,致使不同研究之间的漆酶酶活无法进行比较分析,也造成漆酶产品在酶活质量意义上的混乱。因此,对测定真菌漆酶酶活的各种不同的分光光度法进行了综述和比较分析,认为采用ABTS法作为测定漆酶酶活的方法较具合理性和科学性,建议作为漆酶酶活测定的统一方法。     

关于酶促反应速度与酶反应的初速度的教学

酶促反应速度是酶促反应动力学中的一个基本概念。一定条件下 ,酶催化反应的活力大小要由该反应条件下酶促反应速度来反映和确定 :酶促反应速度越小 ,酶活力越小 ;反之 ,酶促反应速度越大 ,酶活力也越大。在研究底物浓度、酶浓度、温度、ｐＨ、激活剂、抑制剂等因素对酶活力的影响时 ,都必须测定酶促反应的速度。为了排除实验中存在的一些干扰 ,一个酶的酶促反应的速度要在酶促反应进行的初期测定 ,即测定所谓的酶促反应的初速度。在教学过程中 ,学生不易弄清楚酶促反应速度与酶促反应的初速度之间的关系。我们发现 :当一般地问起酶反应速度…     

同工酶与玉米杂种优势研究II.互补酶类型及其在不同器官中的分布

根据我们以往的工作,高优势玉米杂种 的过氧化物酶同工酶酶谱图式之一称为互补 酶— 杂种酶带为其两亲本酶带的互补。类似 的图式BackmanE'.33等曾在玉米胚乳的亮氨酸 氨肤酶及过氧化氢酶,ScandaliOS161曾在氨肤酶, 过氧化氢酶及乙醇脱氢酶,Chiang Pai'53等曾 在水稻过氧化物酶中观察到。     

琼胶酶酶学研究进展

琼胶酶是一类能够降解琼胶多糖的酶的总称,根据其降解琼胶多糖的作用方式不同,分为α-琼胶酶(EC3.2.1.158)和β-琼胶酶(EC3.2.1.81)两种。本文从琼胶酶的酶学性质、晶体结构、催化机制和酶基因研究等方面,综述了近年来国内外琼胶酶酶学的最新研究进展,这将有益于琼胶酶未来的应用。     

海洋细菌Agarivorans albus NBRC102603琼胶酶的分离纯化

利用盐析、分子筛和离子交换等方法对海洋细菌Agarivorans albus NBRC102603分泌的琼胶酶粗酶液进行分离纯化,得到琼胶酶A和琼胶酶B.琼胶酶A纯化倍数为17.51倍,酶比活力为881.82 U/mg;琼胶酶B纯化倍数为16.64倍,酶比活力为838.32 U/mg.纯化的琼胶酶经SDS-PAGE检测,显示为单一条带,其相对分子质量分别为酶A 8.36×104和酶B 3.68×104.     

几丁质酶产生菌筛选鉴定及产酶性能研究

从土壤样品中筛选得到一株高产几丁质酶菌株C65-2,经形态学观察和18S rDNA序列测定,鉴定为Aspergillus fumigatus,对产酶培养基进行初步优化,测得最高酶活可达6.9U/ml,酶活力较优化之前提高了210%。酶学性质研究表明该几丁质酶分子量约为20kDa,酶在60℃下保温50min酶活降为0,最适酶反应温度是55℃,酶反应最适pH为7.0,Mg2+,Cu2+对酶反应有促进作用,Fe3+对酶反应有抑制作用。     

21世纪酶工程研究的新动向

概述了21世纪国际上酶工程研究的新进展和新趋势,着重介绍国际酶工程研究领域的“若干热点”和前沿课题,包括基因工程和蛋白质工程的应用,人工合成酶的模拟酶,核酸酶和抗体酶,分子酶学,功能酶学,酶的定向固定化技术,杂交酶,分子发动机,酶化学技术,非水酶学,糖生物学和糖基转移酶,酶标药物,端粒酶,极端环境微生物和不可培养微生物的新酶种,酶在环境保护方面的应用等。     

He-Ne激光和增强UV-B辐射对小麦幼苗根抗氧化酶的影响

采用5 mW·mm-2He-Ne激光辐照、10.08 kJ·m-2d-1 UV-B辐射及二者组合对冬小麦“临优2018”幼苗进行处理,研究各处理组幼苗根过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性及同工酶变化.研究结果显示,增强UV-B辐射能抑制POD、CAT和SOD的活性,差异显著,关闭了...     

Distribution of aspartate aminotransferase activity in yeasts, and purification and characterization of mitochondrial and cytosolic isoenzymes from Rhodotorula minuta [corrected

The distribution of aspartate aminotransferase activity in yeasts was determined. The number of species of the enzyme in each yeast was determined by zymogram analysis. All the yeasts, except for the genus Saccharomyces, showed two or three activity bands on a zymogram. From among the strains, Rhodotorula minuta [corrected] and Torulopsis candida were selected for examination of the existence of yeast mitochondrial isoenzymes, because these strains showed two clear activity bands on the zymogram and contained a high amount of the enzyme. Only one aspartate aminotransferase was purified from T. candida: the component in the minor band on the zymogram was not an isoenzyme of aspartate aminotransferase. On the other hand, two aspartate aminotransferases were purified to homogeneity from R. minuta [corrected]. The components in the main and minor activity bands on the zymogram were identified as the mitochondrial and cytosolic isoenzymes, respectively, in a cell-fractionation experiment. The enzymatic properties of these isoenzymes were determined. The yeast mitochondrial isoenzyme resembled the animal mitochondrial isoenzymes in molecular weight (subunits and native form), absorption spectrum, and substrate specificity. The amino acid composition was closely similar to that of pig mitochondrial isoenzyme. Rabbit antibody against the yeast mitochondrial isoenzyme, however, did not form a precipitin band with the pig mitochondrial isoenzyme.     

He—Ne激光辐照野桑蚕生物学效应研究

采用一定量He-Ne激光辐照野桑蚕催青卵及蚕肾,并与家蚕杂交,对其子代的蛋白质和酯酶同工酶进行电泳分析,结果发现谱带数目及活性有变化。另外,茧质调查和丝质调查与对照相比也有差异,并发现丝长和纤度特好的变异个体,显示He-Ne激光辐照对野桑蚕生理生化性状有一定影响。     

草菇耐低温菌株的诱变选育与鉴定

在草菇V23原生质体形成和再生的最佳条件下制备原生质体。分别用紫外线(UV),60Co-γ射线,硫酸二乙酯(DES)对原生质体进行复合诱变。初筛、复筛获得耐常规低温(4℃)10d的菌株VH。栽培实验证明:VH在26℃下的生物学效率明显优于V23(CK),且差异极显著。同工酶分析表明:VH过氧化物同工酶,酯酶同工酶谱带数量及酶活性均发生变化;RAPD实验显示:VH相对于V23的变异系数为0.213。VH菇体正常,味道鲜美,食用后无毒副作用。氨基酸组成分析表明:除总氨基酸和谷氨酸含量VH高于V23外,其它氨基酸差异不明显。VH遗传性状稳定,是具有潜在应用价值的优良菌株。     

荞麦愈伤组织分化与过氧化物酶活性及其同工酶关系的研究

在附加不同外源激素的培养基中,龙山荞的子叶愈伤组织表现出不同的分化状态:(1)不分化;(2)分化根;(3)分化芽;(4)分化全苗。四种愈伤组织的过氧化物酶活性的相对比值为1:1.47:5.95:7.78,并且过氧化物酶同工酶谱也存在明显差异。酶带4'为分化愈伤组织所特有;酶带2'为未分化和分化愈伤组织所共有;在分化根和未分化愈伤组织中缺少酶带1';未分化愈伤组织比分化愈伤组织多出酶带3'。     

菘蓝属植物的同工酶分析及其系统学意义

采用聚丙烯酰胺凝胶电泳,比较了菘蓝属（Isatis L.)5种2变种1多倍体品种及1外类群种共计20个样本的酯酶同工酶和超氧化物歧化酶同工酶的酶谱差异,并运用数量分类学的原理和方法对酶谱数据进行了聚类分析。20个样本的酯酶同工酶酶谱共有18条酶带,可分为慢带区（A区）、中带区（B区）和快带区（C区）3个区,其中A区的Rf0.09酶带为所有样本共有,而B区和C区不仅酶带数多,而且活性较强,并表现出很大差异。20个样本的超氧化物歧化酶同工酶酶谱有8条酶带,略有差异。聚类分析结果表明,20个样本被明显分成10组,与形态性状分类结果基本一致。利用酶带的有无、酶带的活性差异以及聚类分析结果,可以初步作出菘蓝属类群间亲缘关系的判定。     

Zymographic demonstration of lactate and malate dehydrogenases isoenzymes in the rodent salivary glands

Summary Analysis of lactate and malate dehydrogenase zymograms of rodent salivary glands showed species and organ specific patterns.Lactate dehydrogenase isoenzyme patterns occupied the middle positions in relation to those of skeletal and heart muscle. Activities of the major salivary glands were in the order submaxillary gland>parotid>sublingual gland. Zymogram of the mouse and rat showed LDH₄ and LDH₅ high activity patterns, while that of the rabbit was the fast moving active one. Hamster salivary gland exhibited a neutral type of the former and the latter.Malate dehydrogenase isoenzyme exhibited very similar patterns for the mouse, rat and hamster. Malate dehydrogenase zymogram of rabbit showed 3 active bands, which was different from the other rodents.     

Ven、K型小麦雄性不育系春性F1杂种的优势表现及与叶绿素含量和同工酶谱的关系

利用Ven、K型小麦雄性不育系与北方春性普通小麦杂交,研究了Ven、K型春性F1杂种的优势表现及其与叶绿素含量、同工酶谱的关系。结果表明：Ven型和K型杂种F1存在显著的个体杂种优质,在主要农艺性状中尤其以单株穗数、千粒重、单株生产力的杂种优势明显,其中单株穗数对单株生产力的贡献最大;相关分析表明：单株生产力与单株穗数呈正相关,相关系数为0.7122;与每穗粒数和千粒重的相关系数分别为－0.1183和0.4941。灌浆期旗叶、倒二叶叶绿素含量与千粒重的相关性最大,呈正相关。杂种F1优势强的组合其种子和苗期的过氧化物同工酶和酯酶的酶谱一般呈双亲互补型或“杂种型”酶带,该特征可作为杂种优势预测的指标。     

Urinary enzyme excretion and renal lactate dehydrogenase isoenzyme pattern in acute HgCl2 nephropathy of rat

The activity of several enzymes with different intracellular sites was determined in urine at various times following nonfatal acute tubular necrosis induced by mercuric chloride administration. The excretion rate of all tested enzymes rose on the 1st and 2nd day; in the next observations (days 7-15) enzymatic values approached the basal values. The lactate dehydrogenase isoenzyme pattern of the renal cortical zone showed an early shift towards cathodic fractions and later (7 days) an increase of middle ones; the normal anodic zymogram recovered after a suitable time interval (30 days). The isoenzymatic changes are related both to the renal hypoxia and to the appearance of less differentiated cells. The behaviour of functional parameters (urine flow, osmolality, urea clearance, creatinine clearance) were well in agreement with the observed enzyme and renal isoenzyme changes.     

Isolation of an 1-aminocyclopropane-1-carboxylate oxidase gene from mulberry (Morus alba L.) and analysis of the function of this gene in plant development and stresses response

Mulberry (Morus alba) is an important crop tree involved in sericulture and pharmaceuticals. To further understand the development and the environmental adaptability mechanism of mulberry, a cDNA of the gene MaACO1 encoding 1-aminocyclopropane-1-carboxylate oxidase was isolated from mulberry. This was used to investigate stress-responsive expression in mulberry. Developmental expression of ACC oxidase in mulberry leaves and spatial expression in mulberry flowers were also investigated. Damage and low-temperature treatment promoted the expression of MaACO1 in mulberry. In leaves, expression of the MaACO1 gene increased in cotyledons and the lowest leaves with leaf development, but showed reduced levels in emerging leaves. In flowers, the pollinated stigma showed the highest expression level, followed by the unpollinated stigma, ovary, and immature flowers. These results suggest that high MaACO1 expression may be predominantly associated with tissue aging or senescence in mulberry.