Testing the Effect of Meat Tenderizer on Human Hair: A Class Project for Nonscience Majors

Use of a commercially available meat tenderizer, a source of an enzyme which can degrade meat protein, was used in a take-home class experiment. Students were asked to test the effects of incubating (their own) human hair in water with and without this enzyme. Students were surprised to see little or no effect of the enzyme on their own hair sample. They were also surprised that there was so much variation in the results (observations). From this experiment, students developed a much better understanding of the scientific method and the importance of experimental controls.     

生物催化反应在工业生产中的应用

本文通过生物催化反应的几种类型简单介绍了生物催化剂－酶应用于工业生产的情况。     

双酶法水解寻氏肌蛤蛋白制备抗氧化肽的研究

文章以寻氏肌蛤为原料制备抗氧化肽,研究木瓜蛋白酶—复合蛋白酶双酶法酶解寻氏肌蛤的工艺条件。以1,1-二苯基-2-苦肼基(DPPH)自由基清除率为测定指标,通过单因素和正交试验确定双酶法制备抗氧化肽的最佳条件。结果显示:pH6.0,酶比例1∶1,[E]/[S]8%,酶解温度60℃,酶解时间6.5h为最佳酶解条件。验证试验表明,在此条件下,抗氧化肽对DPPH自由基清除率为68.70%。     

人体中的钾和钠

本文阐述了钾和钠在人体中的存在,性质及其人体中主要生物学功能。     

Alterations in seedling vigour and antioxidant enzyme activities in Catharanthus roseus under seed priming with native diazotrophs

An experiment was conducted on Catharanthus roseus to study the effect of seed treatments with native diazotrophs on its seedling growth and antioxidant enzyme activities. The treatments had significant influence on various seedling parameters.There is no significant influence on dry matter production with the diazotrophs, Azospirillum and Azotobacter. However, the vital seedling parameters such as germination percentage and vigour index were improved. Azotobacter treatment influenced maximum of 50% germination, whereas Azospirillum and Azotobacter were on par with C. roseus with respect to their vigour index. There was significant difference in the population of total diazotrophs. Azospirillum and Azotobacter between rhizosphere and non-rhizosphere soils of C. roseus had the same trend and were observed at various locations of the study. The activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) were increased to a significant extent due to the treatment with diazotrophs.     

Purification and Biochemical Characterization of D-hydantoinase and D-N-carbamoylase from Burkholderia cepecia, njut01

Hydantoinase and N-carbamoylase play important roles in the production of optically pure amino acids from racemic 5-monosubstituted hydantoins. In this report, hydantoinase and the N-carbamoylase from Burkholderia cepecia, njut01 were purified to homogeneity by chromatography (Pharmacia Explorer 100 system). The substrate specificity, enantioselectivity, pH dependence of activity and temperature stability of the activity were characterized. The results show that the hydantoinase and N-carbamoylase induced from Burkholderia cepecia, njut01 are both strict D-stereo selective enzymes. They both hydrolyze substrates with side chains containing aliphatic and aromatic residues with higher activity and affinity toward aromatic than aliphatic substituted substrates. The hydantoinase is a homotetramer with subtmit molecular weight near 52,000 and is active between pH 6.5 and 10 with an optimum near pH 9.0. The enzyme is active at temperatures up to 60~C, however, it appears instable at higher temperatures. The subunit molecular weight of N-carbamoylase is about 35KD. The N-carbamoylase is active in the pH range from 6.0 to 9.5. The optira-pH is 7.2 and the optinfizing bioconversion temperature of the N-carbamyolase is 52℃.     

水杨酸在果实成熟衰老中的作用

成熟和衰老是果实发育的最后阶段,直接影响到果实品质和贮藏保鲜.成熟和衰老的调控一直被研究者所关注.该过程是一个复杂的代谢过程,除受遗传因子决定外,很大程度上受控于信息物质和多种代谢物质.SA是植物体内普遍存在的一种酚类化合物,被认为是一种植物内源信号分子和新的激素,在植物体内发挥着多种生理功能.最近的研究发现SA是一种乙烯生物合成的有效抑制剂,而乙烯的大量生成是果实趋于成熟衰老的重要特征之一.因此,SA抑制乙烯合成的研究必将成为探索SA延缓果实衰老机理的重要内容.     

两株降解纤维素真菌的分子鉴定及酶活分析

应用刚果红鉴定培养基,从土壤中筛选出两种分解纤维素能力较强的真菌,分别命名为NY01和NY02.滤纸条降解度分析显示,NY01的降解能力高于NY02.应用分子生物学手段,对两株菌rDNA的ITS区域序列分析显示,NY01与木霉的相似性高达99%,NY02与毛霉的相似性高达99%,暗示NY01可能是木霉的一个种,NY02可能是毛霉的一个种.培养基中碳氮比例对两株真菌纤维素降解酶活性的研究显示,在N/C比值较低和较高时,CMC酶和FPA酶活性都低,N/C比值在1∶8时酶活性最高,说明两株真菌降解纤维素的最佳N/C比值是1∶8.     

酶法提取襄麦冬总黄酮的单因素试验研究

以襄麦冬为原料,通过单因素试验,采用酶法提取工艺对影响襄麦冬总黄酮提取的酶的添加量、酶解时间、酶解温度和介质pH值进行了研究.结果表明影响襄麦冬黄酮提取的主要因素为：酶添加量40mg,酶解时间3h,酶解温度50℃,介质pH值为5.0.     

有机溶剂对猪红细胞SOD的活力与构象影响

以猪血为材料,以超氧化歧化酶（简称SOD,EC 1.15.1.1）为研究对象.经有机溶剂沉淀法得SOD酶液,研究甲醇、乙醇、正丙醇、N,N-二甲基甲酰胺（DMF）、二氧六环等有机溶剂对SOD活力影响,结果表明：甲醇、乙醇、正丙醇、DMF对酶活均表现为低浓度激活,但随有机溶剂浓度升高,对酶的激活能力下降甚至转为抑制作用;而二氧六环对酶活表现为激活作用.用荧光光谱法进一步研究甲醇、正丙醇、二氧六环对酶构象的影响,结果显示三种有机溶剂的存在均引起酶构象的改变.