粘红酵母胞内L-苯丙氨酸解氨酶释放的研究

分别考察了液氮冷冻法、超声破碎法、甘氨酸与丙氨酸化学渗透法，不同化学渗透剂TritonX-100、Tween80、Span20、溴代十六烷基吡啶，有机溶剂甲苯、脲及EDTA对粘红酵母（Rhodotorula glutinis）胞内苯丙氨酸解氨酶（即PAL酶）释放及活力的影响，比较发现超声破碎与TritonX-100联用酶释放效果显著，先加入10％Triton X-100渗透6h，再在800W超声破碎30min，蛋白释放率达76．7％。总酶活70．3％，为提取胞内PAL酶提供了一种新方法。     

L-苯丙氨酸解氨酶产生菌的原生质体诱变育种

原始菌株海洋红酵母M1202产生的L-苯丙氨酸解氨酶(PAL),能够逆反应催化反式肉桂酸(t-Ca)生成L-苯丙氨酸。对M1202进行原生质体紫外诱变获得一株转化率为原始菌株115%的菌株TM2,经6次传代,仍具有较好的遗传稳定性。     

粘红酵母苯丙氨酸解氨酶合成条件优化

首先利用Plackett-Burman设计及最陡爬坡试验对在摇瓶中对粘红酵母合成苯丙氨酸解氨酶的培养基和培养条件进行优化筛选,然后通过单因子试验确定最适诱导物。在此基础上,进行发酵罐葡萄糖浓度、产酶pH值以及诱导物添加时间的优化。结果显示优化的发酵培养条件为葡萄糖1g/L,蛋白胨35g/L,NaCl 5g/L,KH2PO4 0.25g/L,（NH4）2HPO4 1.5g/L;接种量4%;初始pH值为5;控制产酶pH值为7;诱导物为L-苯丙氨酸,分别在发酵8h和26h时添加;在上述优化条件下,最高比酶活为40.85U/g,比未优化前提高了7.3倍。     

肉桂酸酶法合成L-苯丙氨酸的研究

研究了粘红酵母hodotorula glutinis ZW194中苯丙氨酸解氨酶生物催化肉桂酸氨化合成苯丙氨酸的反应条件,考察了不同的表面活性剂对转化反应的影响,结果表明,最适转化反应条件:pH 10.5,铵离子浓度8 mol/L,碳酸氢铵/氨水(W/V)=2/8,t-Ca浓度15 g/L,反应时间8 h。最适反应温度为35℃,40℃时依然保持着88%的转化水平,具有抗高温稳定性。在转化反应系统中添加0.20%(W/V)的十六烷基三甲基溴化铵(CTAB)可以提高L-Phe积累量。     

底物和产物对鲜切山药苯丙氨酸解氨酶活性的影响

本实验以山药为材料提取苯丙氨酸解氨酶(PAL),研究底物和产物对山药PAL活性的影响。结果表明:苯丙氨酸促进PAL活性,PAL最适底物浓度为200mg/L,底物浓度过高或过低对酶活力都不利;反式肉桂酸抑制PAL活性,最强抑制浓度为120mg/L,高于或低于这个浓度抑制作用减弱;阿魏酸抑制PAL活性,最强抑制浓度为40mg/L,之后随浓度增加抑制作用减弱,浓度增加至100mg/L时抑制作用最弱,以后随浓度增加抑制作用又增强。     

苯丙氨酸解氨酶重组大肠杆菌产酶条件研究

为了提高重组苯丙氨酸解氨酶(PAL)活力,研究培养基初始pH值、种龄、接种量、装液量和发酵时间对重组PAL活力的影响,并用响应面分析法优化了培养条件。单因素最适培养条件为：发酵培养基初始pH7.0、种龄10h、接种量10%、装液量50ml、发酵时间24h。响应面优化后的结果表明,种龄、接种量和发酵时间对重组PAL活力影响较大,但三者之间没有显著的交互作用。优化后的产酶条件是：种龄13.3h、接种量10.7%、发酵时间25.5h、在此条件下,PAL活力比不优化的培养条件的酶活增加了15%左右,重组PAL酶活达到14.95 U/ml。     

苯丙氨酸解氨酶的研究进展

对苯丙氨酸解氨酶的分布、基本特性、分子结构、各种因子对其活性的影响和生理功能方面作了简要的概述,旨在为该酶的进一步研究提供参考。     

HarpinEa激发烟草叶片过敏性反应与苯丙氨酸解氨酶活性的关系

用不同浓度的HarpinEa溶液处理烟草品种,结果发现:①30μg/mL HarpinEa溶液激发的苯丙氨酸解氨酶(PAL)酶活性最高;②处理叶的上一片叶(上位叶)PAL酶活性明显高于对应半片叶和下一片叶(下位叶)的PAL酶活性;③经激发后不同抗感品种(对烟草根结线虫病和烟草普通花叶病)的PAL酶活性变化在时间上存在一致性;抗病品种与感病品种的PAL酶活性间有明显差异,激发4 d后抗病品种的PAL酶活性显著高于感病品种,PAL酶活性与抗病性间呈正相关关系。     

pH对苯丙氨酸解氨酶重组大肠杆菌生长及产酶的影响

为了提高重组大肠杆菌苯丙氨酸解氨酶的产量和活力，研究了发酵过程中pH对重组大肠杆菌的生长及产酶的影响。结果表明，发酵液pH对菌体生长及酶活有显著的影响，控制发酵液pH可以显著提高菌体量和酶活，当控制pH为7．5时，菌体量和酶活最高。在5L发酵罐分批发酵培养时，控制pH为7．5时的菌体量和酶活分别可以达到OD600=19，总酶活为123U／g，分别比不控制pH高出29％和33％。     

植物苯丙氨酸解氨酶的生物学研究进展

苯丙氨酸解氨酶(phenylanlanine ammonialyase,PAL, E.C.4.3.1.5)作为植物次生代谢特别是苯丙烷途径的关键酶,与植物抵抗病原菌入侵有密切关系,具有重要的植物生理意义.本文综述了植物PAL的存在与分布、分子结构、酶学性质和作用机制,应用酶学和分子生物学知识阐述了其表达调控机理,并在基因水平上对PAL的分子生物学研究进行了展望,旨在为今后PAL在植物抗病应用上提供基础数据.     

Effects of gibberellic acid (GA3) on strawberry PAL (phenylalanine ammonia-lyase) and TAL (tyrosine ammonia-lyase) enzyme activities

Gibberellic acid (GA₃) treatments (30 and 60 μg litre⁻¹) were applied to young plants (Fragaria ananassa cv Chandler). Fruits were harvested at various developmental stages (14, 21, 28 and 35 days from fruit set). Weight and size, phenolic compounds (total polyphenols and anthocyanins) and enzyme activities, phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) were determined. Our aim was to obtain detailed information about PAL and TAL activities related to the strawberry colour during development and ripening processes and to determine the effects of exogenous treatments of GA₃ on PAL and TAL activities. Exogenous treatments of GA₃ improve weight, size and colour of strawberry fruits, and affect PAL and TAL activities. We found that the anthocyanin content and PAL activity are enhanced by the exogenous treatment of GA₃ in the range of 30 μg litre⁻¹. However, with the higher GA₃ treatment, only the anthocyanin content is affected in that way. These findings suggest that gibberellic acid effect on PAL, TAL and ultimately anthocyanin enhancement is dosage related and saturation of the response occurs at 30 μg litre⁻¹. © 1998 SCI.     

荔枝果肉苯丙氨酸解氨酶特性的研究

研究了荔枝果肉中苯丙氨酸解氨酶（L-phenylalanine ammonia-lyase,PAL）的酶学特性。荔枝PAL动力学曲线并不遵循米氏方程,其最适底物浓度为2 mmol/L。在硼砂-硼酸缓冲液中,荔枝PAL的最适反应p H为8.7。PAL不耐酸碱,尤其不耐酸。荔枝PAL的最适反应温度为45℃,高于75℃则易于钝化,具有较强的耐热性。L-酪氨酸和L-半胱氨酸对荔枝PAL均有明显的抑制作用;金属离子中,Fe2+和Fe3+对荔枝PAL活性具有明显的促进作用,而Ca2+、Cu2+、Co2+、Ag+离子则对其活性有明显的抑制作用。      

响应曲面法优化山药中多糖的微波提取工艺

采用微波法辅助提取山药多糖,改进了传统的水提工艺,通过二次回归正交旋转组合设计方法研究了微波功率、微波时间、水提温度和水提时间对山药多糖提取率的影响,建立数学模型,以确定微波提取山药多糖的最优条件。利用模型的响应曲面图及其等高线图,对影响微波提取山药多糖提取率的关键因素及其相互作用进行探讨,得到的优化工艺参数为:微波功率为546W、微波时间为77s、水提温度为64.7℃、水提时间为2.3h,水提效果最佳,山药多糖的提取率为2.60%。     

Optimization of beta-carotene production by Rhodotorula glutinis using high hydrostatic pressure and response surface methodology

ABSTRACT:  Rhodotorula glutinis RG6 was treated by high hydrostatic pressure (HHP) of 300 MPa for 15 min for improving its ability of β-carotene production. After the treatments of 5 repeated cycles, the mutant strain RG6p was obtained, β-carotene production of which reached 10.01 mg/L, increased by 57.89% compared with 6.34 mg/L from parent strain RG6. To optimize the medium for β-carotene fermentation by mutant RG6p, a response surface methodology (RSM) approach was used in conjunction with a factorial design and a central composite design, and the maximum yield of β-carotene (13.43 mg/L), an increase of 34.17% compared to the control, was obtained at a pH 6.7 with an optimum medium (40 mL/250 mL) of yeast extract (4.23 g/L), glucose (12.11 g/L), inoculum (30 mL/L), tomato extract (2.5 mL/L), peanut oil (0.5 mL/L), and (NH₄)₂SO₄ (5 g/L).     

响应面法优化产酸丙酸杆菌丙酸发酵条件的研究

采用Box-Behnken设计和响应面分析法(Response surface methodology,RSM),以产酸丙酸杆菌发酵甘油产丙酸的3个关键因素(培养温度、pH和接种量)为自变量,以丙酸产量为响应值,对上述因素的最佳水平范围进行了探讨与优化。实验结果表明,培养温度和pH对丙酸产量有显著性影响,并据此建立了相关的数学模型。得到的工艺参数的优选结果是:培养温度为29.75℃、pH为6.61、接种量为6.15%(v/v),丙酸产量最大预测值为17.96g/L。经过优化,丙酸产量提高了27.9%,实验值与预测值基本相符。     

Optimization of ring-spinning process parameters using response surface methodology

Several processes are involved in textile industry for yarn production. Ring spinning is the most versatile machine for producing the spun yarn. It is necessary to optimize the ring-spinning process parameters in order to curtail cost and increase the production rate without affecting the yarn quality. In this study, the effects of spinning process parameters namely, spindle speed, roving twist multiplier (roving TM) and yarn TM are studied and have been optimized using three variable Box–Behnken design of Response Surface Methodology. It is determined that spindle speed of 17,000?rpm with 4.1 TM for yarn and 1.3 TM for roving results are the best optimal responses.     

明绿豆苯丙氨酸解氨酶的分离纯化及性质初步研究

为了研究明绿豆中苯丙氨酸解氨酶(PAL)的动力学特性,采用35%和65%饱和度的硫酸铵分级沉淀、DE-52阴离子交换层析方法对明绿豆中的PAL进行了分离纯化,并对其基本性质做了初步研究。结果表明,PAL的纯化倍数为6.982 9,蛋白质得率为4.65%,酶得率为32.45%。PAL在硼砂-硼酸缓冲溶液中适宜的p H范围为7.6~9.0,最适p H有2个:8.0和8.6。PAL适宜的温度范围为35~45℃,最适反应温度为40℃。得到PAL的2个Km值,分别是:Km1为6.94×10-5mol/L,Km2为1.23×10-4mol/L。本研究结果可为进一步研究和开发明绿豆的PAL提供参考。     

Modeling the bagging behavior of worsted fabrics using response surface methodology

In this paper, we have studied the effect of a number of loading cycles on fabrics bagging behavior, and then investigated the influence of factors such as sample weight, test speed, and sphere diameter on the worsted fabrics bagging behavior using response surface method (RSM). Six worsted fabric types with different weights were prepared and then the bagging properties of these fabrics were measured using a newly developed test method. Bagging parameters including bagging force, work, fatigue, resistance, hysteresis, and residual height are calculated. Then, a statistical model (RSM) was used for the experimental plan (with these factors) to determine the runs of an experiment (or selected points). The experimental results showed that sample weight and sphere diameter have a significant effect while test speed has no significant effect on the bagging parameters. Also, the fitted models of bagging parameters are obtained and coefficient effects are estimated.     

Possible regulatory role of phenylalanine ammonia‐lyase in the production of anthocyanins in asparagus (Asparagus officinalis L)

The regulatory role of phenylalanine ammonia‐lyase (PAL) in the light‐induced accumulation of anthocyanins in the epidermis of asparagus spears has been analysed. A correlation between the stimulation of PAL activity and the rise in total anthocyanin content has been observed. Light radiation induced PAL activity, which in turn stimulated anthocyanin accumulation, a hypothesis which has been confirmed by treating asparagus spears with S‐carvone, an inhibitor of PAL activity. A marked delay was observed in the rise in PAL activity and total anthocyanin content in asparagus spears treated with this compound during light irradiation. PAL activity and anthocyanin synthesis continued when the spears were stored in darkness for 5 days after being subjected to light, but the inhibitory effect of S‐carvone remained during this storage. When the asparagus spears were immersed in water for 20 h, no PAL activity could be detected and scarcely any total anthocyanin content was measured. However, after 5 days of storage in darkness a sharp upsurge in PAL activity was found, which was not translated into a parallel increase in total anthocyanin content. Copyright © 2005 Society of Chemical Industry