脱脂沙棘籽制备活性多肽的研究北大核心CSCD

本文比较了用巯基蛋白酶酶解沙棘籽蛋白所得酶解多肽对乙醇脱氢酶（ADH）的激活率效果。结果表明,木瓜蛋白酶的酶解产物对ADH的激活效果最好。该活性多肽的最佳制备条件为,酶解pH为6．5,温度为50℃,酶解时间3．5h,加酶量为4000U／g。体外实验表明,木瓜蛋白酶水解产物中ADH激活率较高的为500—2000Da的多肽,达57．52％,与未分级的酶解液相比,活性提高显著（P〈0．01）。分子量在2000～3000Da的沙棘多肽也具有一定的ADH激活率,为35．09％,说明具有ADH激活率的活性多肽分子量为500～3000Da。木瓜蛋白酶酶解液经膜分离处理后,收集得到的500—3000Da的多肽组成占总肽及氨基酸质量的66．50％。     

米糠蛋白抗氧化活性肽的制备

以水解度(DH％)和对DPPH自由基清除率为指标,筛选出制备米糠蛋白抗氧化活性肽的最适蛋白酶.研究最适蛋白酶的酶解条件,探讨底物浓度、蛋白酶的加入量、pH值、酶解时间等因素对水解度(DH％)和DPPH自由基清除率的影响;在单因素基础上采用Box-Behnken响应曲面中心组合设计法,对酶解米糠蛋白的工艺进行优化.试验结果表明,在加酶量13970.82 U/g,时间3.05h,底物浓度4.97％的水解条件下,米糠蛋白的水解度能够达到23.67％,活性肽对DPPH自由基清除率达到64.26％.     

瓜尔豆种皮酶解提取物抗氧化性研究

以3种蛋白酶对瓜尔豆种皮活性肽进行酶解分离,通过总抗氧化能力测定,筛选出木瓜蛋白酶水解提取物总抗氧化能力最强,分别为碱性蛋白酶和中性蛋白酶水解提取物的1．95倍和3．34倍。在清除超氧阴离子自由基的测定中,木瓜蛋白酶水解提取物也表现出较强的清除能力,清除率随水解溶液浓度的增加呈正量效关系,当溶液浓度为5．45mg/mL时,清除率达43．37％。通过实验证实瓜尔豆种皮酶解提取物与大豆多肽一样有较强的抗氧化能力。     

脱脂沙棘籽制备活性多肽的研究

本文比较了用巯基蛋白酶酶解沙棘籽蛋白所得酶解多肽对乙醇脱氢酶(ADH)的激活率效果。结果表明,木瓜蛋白酶的酶解产物对ADH的激活效果最好。该活性多肽的最佳制备条件为,酶解p H为6.5,温度为50℃,酶解时间3.5 h,加酶量为4 000 U/g。体外实验表明,木瓜蛋白酶水解产物中ADH激活率较高的为500~2000 Da的多肽,达57.52%,与未分级的酶解液相比,活性提高显著(P0.01)。分子量在2000~3000 Da的沙棘多肽也具有一定的ADH激活率,为35.09%,说明具有ADH激活率的活性多肽分子量为500~3000 Da。木瓜蛋白酶酶解液经膜分离处理后,收集得到的500~3000 Da的多肽组成占总肽及氨基酸质量的66.50%。     

酶解天山马鹿血分离制备抗疲劳肽的研究

本文选用木瓜蛋白酶水解天山马鹿血,制备具有抗疲劳活性的多肽,并测定其抗疲劳活性,并对具有活性的多肽进行进一步的分离制备.结果:确定最佳的酶解工艺条件为温度52℃;pH值为7.4;酶与底物浓度比(E/S)为9;底物浓度([S])为8%.选取3种水解产物(1组、2组、3组)进行小鼠负重游泳实验.结果表明:含水解产物的1组能使小鼠游泳力竭最长时间达到250 min(P＜0.001),第2组、第3组和空白对照组为114、82和77 min;在相同游泳时间40 min内,第1组肌乳酸含量比对照组减少44.9%;体内肝糖元消耗量减少38.4%,表明:第1组木瓜蛋白酶水解产物(水解度19.8%)能够明显延长小鼠游泳时间,增强运动耐力,具有显著的抗疲劳作用.     

双酶法制备螺旋藻多肽的工艺研究

选用碱性蛋白酶和木瓜蛋白酶结合的双酶法对螺旋藻蛋白进行水解。其中,对木瓜蛋白酶水解螺旋藻蛋白的工艺进行优化。以水解度为指标,研究了酶解时间、酶与底物比、pH和酶解温度4种因素对酶解反应的影响。在此基础上设计了3因素(加酶量、酶解温度和pH)3水平的响应面试验。结果表明碱性蛋白酶水解螺旋藻蛋白的最佳酶解条件为:加酶量4300 U/g,pH 7.0,酶解温度55℃,酶解时间160 min;木瓜蛋白酶的最佳酶解条件为:酶底比为4.5%,酶解温度60℃,pH 6.5,酶解时间210 min。利用碱性蛋白酶和木瓜蛋白酶结合的双酶法制得的多肽水解度可达32.90%,与单酶法相比,水解度明显提高。     

猪皮胶原蛋白水解产物中的抗氧化活性肽的分离及其氨基酸组分

利用不同蛋白酶水解猪皮胶原蛋白,根据水解产物对自由基的清除率,筛选最适蛋白酶的组合,筛选抗氧化活性较高的肽类,并进行氨基酸分析.结果表明:胃蛋白酶→木瓜蛋白酶→菠萝蛋白酶为酶解胶原蛋白的最佳组合;分离纯化得到了三种具有较高抗氧化活性的肽;氨基酸组分分析显示:P1′、P2′和P3′组分具有自由基清除作用的关键氨基酸甲硫氨酸、酪氨酸和组氨酸等.     

马鹿茸血免疫活性肽的制备及其活性研究

本文以免疫活性和DPPH·的清除能力为指标,研究了用木瓜蛋白酶与中性蛋白酶水解马鹿茸血制备活性肽的条件,并初步探讨了此活性肽的免疫活性与对DPPH·清除能力之间的关系.实验结果表明:当[E/S]为9000 U/g时,中性蛋白酶和木瓜蛋白酶的水解温度各为50和45 ℃,pH各为7.1和6.8,分别水解2和1.5 h可以获得最佳的酶解效果.在相同蛋白含量的情况下,两酶复合水解物的淋巴细胞增殖率比单酶水解增加了20.8%.免疫活性与DPPH·清除能力之间存在一定的相关性(r=0.957,P<0.01).     

酶解鹿茸血ACE抑制活性及其与抗氧化活性关系的研究

实验采用木瓜蛋白酶和Alcalase碱性蛋白酶水解鹿茸血,在不同的时间取样,分别测定血管紧张素转化酶(ACE)抑制率、二苯代苦味肼基自由基(DPPH.)清除率和羟自由基(.OH)清除率。结果表明Alcalase蛋白酶水解产物ACE抑制活性和DPPH.清除活性较强,其水解3h的产物ACE抑制率为90.63%,DPPH.清除率为14.40%;木瓜蛋白酶水解5h的产物.OH清除率最高,为96.7%。用SPSS10.0软件分析结果,发现ACE抑制率与DPPH.清除率具有显著相关性。     

双酶法酶解豌豆蛋白制备高抗氧化多肽的研究

以水解度及DPPH自由基清除能力为指标优选出1398中性蛋白酶和胰蛋白酶分步酶解豌豆分离蛋白,所得豌豆蛋白水解产物(pea protein hydrolysate,PPH)中相对分子量小于2 KDa的多肽占77.07％,对DPPH的半清除浓度(IC50)为3.01 mg/mL;PPH经Sephadex G-25凝胶层析和两次RESOURCETM 3RPC反相层析纯化获得高抗氧化活性峰,经反相层析鉴定为层析纯,当浓度在0.2 mg/mL时,对DPPH的清除率达到62.03％,与同浓度下的谷胱甘肽对DPPH的清除率相近(66.82％).     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Principles of organization and evolution of systems of regulation of functions

Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms. The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning of physiological systems and organs of the living organism