乌鳢蛋白消化酶活性的研究

研究了温度及不同蛋白源饲料（泥鳅Ｍｉｓｇｕｒｎｕｓａｎｇｕｉｌｉｃａｕｄａｔｕｓ和黄豆饼）对乌鳢（Ｏｐｈｉｏｃｅｐｈａｌｕｓａｒｇｕｓ）蛋白消化酶活性的影响．结果表明：温度可显著影响蛋白酶活性;胃蛋白酶、肠道蛋白酶及肝胰脏蛋白酶的最适温度分别为３０℃、３０℃和２５℃;在最适温度及同等温度条件下,胃蛋白酶活性均比肠道蛋白酶及肝胰脏蛋白酶活性高．饲喂后９ｈ,黄豆饼组胃蛋白酶、肠道蛋白酶达最大活性,泥鳅组为１２ｈ．     

从石蜡包埋组织高效提取RNA的优化及Shh的RT-PCR检测

从石蜡包埋组织中提取高质量的RNA是对肿瘤实体组织进行分子生物学研究的重要方法之一．利用人的胃肠道肿瘤材料，通过蛋白酶K消化，经酚-氯仿、异戊醇抽提去蛋白及异丙醇沉淀，优化了1套从石蜡包埋组织中提取RNA的方法，提高了所提取RNA的质量和产量．所得RNA经电泳检测，并进行RT-PCR扩增Shh(sonic hedgehog)信号分子，结果良好．故认为此提取RNA的方法值得推广．     

Transgenic tobacco plants harboring tomato proteinase inhibitor II gene and their insect resistance

The plant expression vectors pBCT2 and pBT2 were constructed with the cDNA sequence (tin2) and genomic DNA sequence (tin2i) of tomato proteinase inhibitor II gene respectively. Then the two expression vectors were transferred into tobacco via the Agrobacterium tumefaciens strain LBA4404, and transgenic tobacco plants were generated. Molecular analysis and trypsin activity assay showed that both cDNA and genomic DNA were expressed properly in the transgenic plants. Insecticidal activities in these transgenic plants indicated that transgenic tobacco plants carrying tin2i sequence were more resistant to 2-instar larvae of Heliothis armigera Hubner than those carrying tin2 sequence. Therefore the intron of tin2i sequence might be a contributor to insecticidal activity of the transgenic tobacco.     

总状毛霉MR 137-3发酵蛋白酶的提取与催化效应

用CO2激光辐射总状毛霉MR137，获得高产蛋白酶变异株MR137—3。MR137—3经固体发酵后，用0．3mol／L NaCl，40℃提取粗酶液，再经DC-30型中空纤维素柱浓缩。制得的MR 137—3蛋白酶产品经检测证明其安全性好，并且对牛奶蛋白的水解效率优于市售木瓜蛋白酶。提取粗酶后的残渣中氨基酸含量达20．28％，可以作为优质的饲料资源。     

马铃薯蛋白酶抑制因子特性的研究

本文研究了马铃薯蛋白酶抑制因子的稳定性及其对胰蛋白酶和胰凝乳蛋白酶的抑制能力,结果表明：该抑制因子对胰蛋白酶活性的抑制作用较弱,最大抑制程度为６５％;对胰凝乳蛋白酶活性的抑制作用较强,抑制程度最高可达９５％以上,并且,它对ｐＨ及温度的变化均具有较强的稳定性．     

Acylation of amino functions of proteins with monomethoxypoly (ethylene glycol)-N-succinimide carbonate

Monomethoxypoly(ethylene glycol)-N-succinimide carbonate (SC-PEG) was used to prepare PEG-lysozyme, PEG-papaya proteinase III, PEG-catalase, and PEG-lactoperoxidase conjugates. SC-PEG produced extensively modified enzymes under mild conditions (pH 7.0; 25°C) within a couple of hours. PEG-enzyme conjugates showed equal or even greater specific activity provided that low-molecularweight substrates were used to evaluate the biological activities. However, papaya proteinase III and lysozyme lost their proteolytic and bacteriolytic activities, respectively, on conjugation with PEG. This was most probably because of steric factors, since no drastic conformational changes could be detected after conjugation of these enzymes with PEG chains. Unlike these enzymes, the secondary structures of the two hemoproteins were somewhat affected by the covalent attachment of PEG chains as shown by FTIR experiments. These results confirmed the potential usefulness of SC-PEG, for which a novel route of synthesis making use ofN,N′-disuccinimidyl carbonate was described.     

33 ku protein associated several polypeptides with nearly the same molecular weight but not the same isoelectric point

The 33 ku protein, prepared from NaCl-treated PS II particles, has shown an single band by SDS-PAGE. After being dialyzed against the low-osmotic medium at 4°C, it has been found that the 33 ku protein degraded into several small fragments. This result suggests that the preparations of 33 ku protein probably contain some latent proteinases. It has also been found, by the 2-D electrophoresis and IEF, that the preparations of 33 ku protein not dialyzed against the low-osmotic medium contain several polypeptides with nearly the same molecular weight but not the same isoelectric point as the 33 ku protein.     

枯草杆菌蛋白酶与茜素氨羧络合剂作用研究

应用UV光谱法研究在pH 4.20的酸性溶液中,枯草杆菌蛋白酶(BSP)与茜素氨羧络合剂(ALC)的相互作用。测得生成的缔合物的最大吸收峰为510 nm,与试剂相比红移85 nm。应用平衡透析法、摩尔比法和双波长法进行测定,结果表明,表观摩尔吸光系数ε_B＝6.68×103 L·mol-1·cm-1,表观结合常数K＝7.25×106 L·mol-1,平均结合数n＝10,与BSP的活性部位基本吻合。研究发现,该反应基本符合Scatchard模型,认为是BSP与ALC之间以电荷力为主、疏水力为辅综合作用的结果。     

高产酸性蛋白酶黑曲霉菌种选育

从麸醋醋母中分离出黑曲霉Asp5609,用15W紫外灯照射8min,照射距离30cm,在暗处30℃培养3d后挑取透明圈大的茵落用亚硝基胍诱变处理,筛选出高产酸性蛋白酶变异株A5p5609-7．在培养基pH5．0,含水量50％,培养时间60h,变温培养等优化条件下获得固体发酵达35000U／g．干基的酸性蛋白酶物料．     

Highly biodegradable copolymers composed of chiral depsipeptide and L‐lactide units with favorable physical properties

Syntheses of copolymers composed of optically active depsipeptides (3,6‐dimethyl‐2,5‐morphorinedione) and L ‐lactide—poly(L ‐3,L ‐6‐dimethyl‐2,5‐morphorinedione‐co‐L ‐lactide), poly(L ‐3,DL ‐6‐dimethyl‐2,5‐morphorinedione‐co‐L ‐lactide), and poly(L ‐3,D ‐6‐dimethyl‐2,5‐morphorinedione‐co‐L ‐lactide)—were examined in an effort to improve the biodegradability and physical properties of homopoly(L ‐lactide). In degradation tests, the copolymers composed of 3,6‐dimethyl‐2,5‐morphorinedione and lactide in the ratios 10/90 to 13/87 exhibited high biodegradability toward proteinase K, whereas a homopolymer, poly(L ‐lactide), exhibited very poor biodegradability (only 50% after 200 h). These polymers composed of 3,6‐dimethyl‐2,5‐morphorinedione/L ‐lactide in 11/89 to 13/87 ratios also degrades rapidly after being in compost for 30 days. The resulting copolymers, however, showed relatively low elongation properties. Therefore, ternary copolymerizations of L ‐3,DL ‐6‐dimethyl‐2,5‐morphorinedione, ?‐caprolactone, and L ‐lactide were explored in an effort to improve their mechanical properties, especially the elongation, and sufficient results were obtained with an approximate ratio of 3/11/86. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 302–316, 2002