黄尾鲴不同组织中LDH同工酶的研究

[目的]研究黄尾鲴不同组织的LDH同工酶。[方法]采用垂直板聚丙烯酰胺凝胶电泳技术和特异性染色方法对黄尾鲴的肝、肾、眼、心4种组织的LDH同工酶进行分析。[结果]酶谱的表达具有明显的组织特异性。酶带由3个基因座位(LDH-A、LDH-B、LDHC)编码,在4种组织中共检测到14条带,其中,心和肾7条带,眼6条带,肝14条带。在PAGE胶趋向阴极侧检测到6条肝脏组织所特有的LDH-C基因编码带。在各组织LDH酶带表达活性上,心中LDH-2、LDH-3和LDH-5表达占优势,肾中LDH-2、LDH-7和LDH-3表达占优势,肝中LDH-13、LDH-9和LDH-12表达占优势,眼中LDH-5、LDH-2和LDH-7表达占优势。[结论]该研究为丰富黄尾鲴遗传学基础研究、遗传育种种质标准的建立和种群生化遗传结构分析提供科学依据。     

Lactate dehydrogenase Isozymes: substrate inhibition in various human tissues

The total lactate dehydrogenase (LDH) in whole homogenates of various human tissues reacts more similarly toward pyruvate and lactate at 25 degrees C than expected from the marked differences in substrate inhibition at this temperature between isolated, purified LDH-1, and LDH-5. At 37 degrees C, LDH-5 closely resembles LDH-1 in extent of inhibition by substrate. These results are incompatible with the theory that differences in degree of isozyme inhibition by substrate have resulted in predominance of LDH-5 in aerobic tissues and predominance of LDH-1 in aerobic tissues.     

Lactate dehydrogenase isozymes: kinetic properties at high enzyme concentrations

The kinetic properties of lactate dehydrogenase (LDH) isozymes have been determined at high enzyme concentrations. Spectrophotofluorometric assays revealed that the extent of substrate inhibition of LDH-1 and LDH-5 depends on enzyme concentration. At high enzyme concentrations, in the range of those that exist in most mammalian cells, no inhibition by pyruvate occurred. Pyruvate concentrations up to and including 20.0 millimoles per liter were used for each isozyme at 25 degrees and 40 degrees C at pH 7.0 and 7.4. These results suggest that substrate inhibition of LDH may not occur in vivo but only in vitro after appreciable dilution from physiologic enzyme concentrations. These experiments provide further evidence against the theory that substrate inhibition of LDH-1 in vivo accounts for the distribution of LDH isozymes within various tissues. They raise the possibility that, for other enzymes, kinetic properties determined at highly dilute concentrations in vitro may also be quite different from kinetic properties at the much higher concentrations that exist in vivo.     

低温胁迫下黑龙江林蛙肝脏酶活性变化

初步分析了低温胁迫下黑龙江林蛙肝脏超氧化物歧化酶(SOD)、乳酸脱氢酶(LDH)、6-磷酸葡萄糖脱氢酶(G6PDH)及酯酶(EST)酶活性的变化.结果表明:1℃组的黑龙江林蛙肝脏SOD、LDH-1及EST的酶活性显著高于14℃组(P＜0.05),而2组的LDH、G6PDH及EST总酶比活力无显著性差异.为适应低温环境,黑龙江林蛙肝脏某些酶活性显著增加,维持了机体代谢的稳定.     

山东青山羊血清乳酸脱氢酶同工酶谱型的研究

用琼脂糖凝胶电泳技术,测定山东特有的羔皮青山羊血清 LDH 同工酶谱型。结果表明,青山羊血清 LDH 同工酶谱的基本特点是LDH-1>LDH 3>LDH 2>LDH-5>LDH-4。这与其它山羊相比,表现一定差异。部分青山羊的母羊除表现正常的5条谱带外,还表现1条新的酶带,暂称为 y 带,其电泳迁移率介于 LDH-3与 LDH-4,近乎 LDH-3。     

Lactate dehydrogenase isozymes: further kinetic studies at high enzyme concentration

By competition with lactate dehydrogenase (LDH) for nicotinamide adenine dinucleotide (NAD), commonly occurring intracellular proteins, such as glyceraldehyde-3-phosphate dehydrogenase, malate dehydrogenase, and albumin, can protect LDH-1 and LDH-5 from inhibition and ternary complex formation with NAD and pyruvate. The existence of intracellular proteins that compete with LDH for NAD renders unphysiological a model for estimating the extent of intracellular LDH inhibition based on incubations of only LDH, NAD, and pyruvate.     

牦牛乳酸脱氢酶-1两种遗传变异体的纯化及酶学特性比较

 【目的】从乳酸脱氢酶（LDH）水平上探索牦牛(Bos grunniens)低氧适应性分子机制。【方法】利用聚丙烯酰胺凝胶电泳分析牦牛组织中LDH同工酶谱;用比色法测定牦牛、黄牛和水牛心脏、肝脏和肌肉组织中LDH总活力;采用染料亲和层析和DEAE-Sephadex离子交换层析从牦牛心肌组织中纯化LDH1（由4个H亚基组成）的2种遗传变异体,进行酶学性质的比较。【结果】电泳方法检测发现牦牛LDH1存在2种遗传变异体,根据电泳迁移率分别命名为快型和慢型（LDH1-F和LDH1-S）。获得纯化的牦牛LDH1-F和LDH1-S,比活力分别为21.4 U?mg-1蛋白和17.8 U?mg-1蛋白,在SDS-PAGE和PAGE上均显示1条区带。2种变异体以NADH为底物的米氏常数（Km）值差异不大,均显著高于普通牛的LDH1;以丙酮酸钠为底物的Km值LDH1-F小于LDH1-S。试验进一步比较了携带不同LDH1变异体的牦牛心脏、肝脏和肌肉组织中LDH总活力和各种同工酶谱,未见显著差异,而牦牛心脏、肝脏和肌肉组织中LDH总活力显著或极显著低于黄牛和水牛。【结论】牦牛LDH1 2种遗传变异体的Km值存在差异,且Km(NADH)高于普通牛;牦牛心脏、肝脏和肌肉组织中LDH总活力低于普通牛。     

厌氧胁迫下薏苡和玉米中代谢物质和酶类的变化

研究了厌氧胁迫下薏苡(Coix lacryma jobiL.)和玉米(zea mayL.)几种代谢物质和酶类的变化。厌氧胁迫后二者根系与叶片中的可溶性糖和丙酮酸含量都表现为下降,游离氨基酸含量、乙醇脱氢酶(ADH)和乳酸脱氢酶(LDH)活性都表现为上升,薏苡游离氨基酸增幅高于玉米;玉米的ADH和LDH变化幅度较大。结果表明,在厌氧耐受过程中关键的代谢物质可能是游离氨基酸而不是可溶性糖;ADH和LDH受到厌氧诱导,其厌氧胁迫前的活性高低可能是耐涝性的决定因素。     

有氧运动对小鼠心肌、骨骼肌线粒体SOD、MDA、LDH的影响

探讨了有氧运动对小鼠心肌、骨骼肌线粒体SOD、MDA、LDH的影响.结果表明,在3 h游泳运动后,试验组与对照组小鼠心肌中SOD的活性无显著差异(P>0.05),而骨骼肌中SOD活性显著降低(P<0.05);试验组小鼠心肌、骨骼肌线粒体中MDA的含量均有所升高,差异显著(P<0.05):LDH活性有所降低,但差异不显著(P>0.05).说明有氧运动对小鼠骨骼肌中SOD活性和小鼠心肌、骨骼肌线粒体中MDA含量的影响显著,但对LDH活性无显著影响.     

生长期牦牛血清和组织中LDH活性的测定

对同一海拔地区不同发育期牦牛血清和组织中乳酸脱氢酶(LDH)活性进行了测定,对血清中乳酸脱氢酶同工酶进行了比较.结果表明,1日龄和1月龄组血清中LDH活性均显著高于其余两个年龄组,且1月龄组血清中LDH的活性显著升高,差异均显著(P＜0.05),6月龄组血清LDH的活性已降低到成年组的水平;组织中LDH活性均低于血清(P＜0.05),1日龄和1月龄组肝脏和骨骼肌中LDH活性均高于6月龄组,1月龄组心肌中LDH的活性明显较高,差异显著(P＜0.05),其余组织无统计意义;1月龄组中血清LDH同工酶活性最强,其LDH5+LDH4活性明显高于其余3个年龄组.在高原低氧环境下,牦牛在生长发育的特定阶段需增强无氧代谢机制,以满足机体能量代谢的需要.     

不同体力活动水平高校女性教师递增负荷运动前后血清心肌酶的比较研究

目的：研究不同体力活动水平女性教师递增负荷前后血清心肌酶的差异,进而评估不同体力活动水平女性教师运动中可能出现的心脏风险。方法：对受试者进行体力活动问卷调查,从中筛选87名健康女性教师进行递增负荷试验,测试运动测试前后的心肌酶指标进行比较分析。结果：1）运动前安静状态下,体力活动不足组心肌酶各指标值均低于中、高水平体力活动组,其中体力活动不足组CK-MB显著的低于中等组（P<0.05）并且非常显著的低于高等组（P<0.01）。2）运动测试后,体力活动高水平组CK值显著的高于体力活动不足组（P<0.05）,除AST以外,其余心肌酶水平随着体力活动水平的升高而升高。其中体力活动不足组AST值超过正常值范围,提示心肌组织出现了一定的损伤。3）除中等和高水平体力活动组的CK-MB运动后比运动前有所下降外,其余各组指标运动后都有所升高,特别是三组的CK、AST都非常显著的升高（P<0.01）,从运动前后差值比较分析来看,不足组的CK、AST增加值显著的高于中等组和高等组（P<0.05）。结论：1. 体力活动不足的高校女性教师安静状态下的心肌酶水平较低。2. 递增负荷运动会引起高校女性教师心肌细胞出现一定程度的损伤,运动后血清心肌酶水平有所升高,而且体力活动不足女性的损伤更为严重,主要表现在心肌酶指标中的CK和AST。     

Lactate dehydrogenase isozyme patterns of human platelets and bovine lens fibers

Human platelets and bovine lens fibers contain lactate dehydrogenase-3 (LDH-3) as the predominant isozyme but only very faint traces of LDH-5. Since the platelets and lens fibers, like mature human erythrocytes, lack a nucleus, the results strengthen the case for a previously developed association between LDH-5 and the cell nucleus. These three cell types are mainly anaerobic, and therefore their isozyme patterns are incompatible with the theory that anaerobic tissues exhibit predominantly LDH-5 and aerobic tissues mainly LDH-1.     

Purine overproduction in man associated with increased phosphoribosylpyrophosphate synthetase activity

In hemolyzates from red cells of two brothers with purine overproduction and gout, activity of phosphoribosylpyrophosphate synthetase is more than twofold greater than that measured in normal or other gouty individuals. The increased enzyme activity, which is also demonstrable in fibroblasts of the one patient tested, is associated with increased production of 5-phosphoribosyl-1-pyrophosphate by intact cells, an indication that the enzyme abnormality is the basis for the purine overproduction. This genetic abnormality is an example of an increased enzyme activity producing a disease state.     

乌鳢不同组织的LDH同工酶的研究

本文报道了应用聚丙烯酰胺凝胶垂直板电泳分离和研究成体乌直脏、骨骼肌、肾脏、１心肌、卵巢、脑、脾脏,眼和血清９种组织器官中ＬＤＨ同工酶。结果表明：除眼、脾组织中的ＬＤＨ分别为７条和５条同工酶带;肝脏、骨骼肌为１条和２条酶带外,多数组织中ＬＤＨ表现为４条酶带。进一步的分析表明,ＬＤＨ同工酶在活力和组织分布方面具有明显的特异性;血清,卵巢,骨骼肌的ＬＤＨ１,活力最强,而在其它组织中则ＬＤＨ４的活力最强。     

花斑副沙鳅七种同工酶的组织特异性表达

采用聚丙烯酰胺垂直梯度凝胶电泳方法,对花斑副沙鳅(Parabotia fasciata Dabry)的鰓、心、肝胰脏、肠、肾、肌肉、眼、脑8种组织中的过氧化氢酶(CAT)、酯酶(EST)、乳酸脱氢酶(LDH)、苹果酸脱氢酶(MDH)、过氧化物酶(POD)、超氧化物歧化酶(SOD)和醇脱氢酶(ADH)进行了分析。结果表明,花斑副沙鳅的7种同工酶表达具有明显的组织特异性,8种组织中检测出3种CAT同工酶、8种EST同工酶、4种LDH同工酶、8种MDH同工酶、10种POD同工酶、10种SOD同工酶、10种ADH同工酶表达。其中,CAT-3、EST-7仅在肝胰脏表达,LDH-4、SOD-9、ADH-3仅在肾表达。     

丽斑麻蜥和山地麻蜥组织LDH同工酶谱比较研究

应用灵敏度较高的聚丙烯酰胺凝胶电泳技术，结合尿素抑制实验．对丽斑麻蜥和山地麻蜥不同组织（如脑、肝、小肠、心肌、肾、睾丸、肌肉和眼球）中ＬＤＨ同工酶的分布特征和性质进行比较研究。实验结果，两种麻蜥不同组织ＬＤＨ同工酶酶谱十分相似，并具有组织器官特异性、在心肌和小肠等组织中ＬＤＨ同工酶表现出一定的种间特异性。ＬＤＨ同Ｌ酶对尿素抑制的敏感程度依次为ＬＤＨ３＞ＬＤＨ２＞ＬＤＨ１。ＬＤＨ同工酶分布特征与其生理功能和生活环境有一定关系。     

慢性冷热应激对三河牛血液生化指标及相关基因表达的影响

为研究冷热应激对三河牛血液生化指标及相关基因表达量的影响,利用实时荧光定量PCR和ELISA方法检测冷热应激期和非应激期血清中肌酸激酶(CK)、乳酸脱氢酶(LDH)、葡萄糖(GLU)和尿素氮(BUN)含量及淋巴细胞中HSP70家族基因(HSPA1A、HSPA1B、HSPA8)mRNA表达量。结果显示:1)冷热应激期血清中CK和LDH活性相比非应激期均升高,热应激期升高尤为显著(P0.05);热应激期GLU含量相比非应激期显著降低(P0.05);热应激期BUN含量略低于非应激期,差异不显著;冷应激期GLU和BUN含量相比非应激期均显著升高(P0.05)。2)冷热应激期淋巴细胞中3个HSP70家族基因mRNA表达量相比非应激期显著升高(P0.05)。结果表明,慢性冷热应激改变了血液中酶的活性、糖和蛋白质的代谢,从而导致奶牛的一些组织细胞的损伤和营养代谢的紊乱,并冷热应激时血液淋巴细胞中HSP70家族基因mRNA表达量的上升,可在一定程度上反映其对动物机体的保护水平。     

分布稻田的三种不同体色泥鳅组织LDH同工酶的研究

本文报道了应用聚丙烯酰胺凝胶垂直板电泳分析研究分布于稻田的三种不同体色泥鳅在心肌,骨骼肌,肝脏,眼,血清七种组织器官中ＬＤＨ同工酶的表达特征。电泳图谱表明,这些组织分布和活力均具有明显的组织特异性;在脑组织ＬＤＨ２活性最强,其它组织如血清,眼,卵巢,肝脏,心肌等组织中ＬＤＨ３活力最强,此外,在肝脏中存在由Ｌｄｈ－Ｃ编码的Ｃ带。     

镉对大鼠睾丸匀浆中某些生化指标的影响

镉是环境中常见的重金属之一，对生殖系统的毒性较强。经研究发现，镉可引起大鼠睾丸组织中某些生化指标的变化。乳酸脱氢酶（ＬＤＨ）和酸性磷酸酶（ＡＣＰ）的活性随着镉染毒剂量的增加而降低，而碱性磷酸酶（ＡＫＰ）未发现明显变化。乳酸脱氢酶同功酶ＬＤＨ１，ＬＤＨ２、ＬＤＨ３和ＬＤＨ４，在１．０９到８，７２ｕｍｏｌ／ｋｇ时，受到不同程度的抑制．但是，ＬＤＨ５却呈双相性变化，在１，０９、２．１８和４．３６ｕｍｏｌ／ｋｇ组，其活性升高，而在８．７２０ｕｍｏｌ／ｋｇ组，其活性下降。在ＬＤＨ同功酶中，ＬＤＨ－ｘ、ＬＤＨ４和ＬＤＨ５对镉较敏感。     

Lactate dehydrogenase of trout: hybridization in vivo and in vitro

Speckled trout and lake trout contain five forms of lactate dehydrogenase, but a diflerent electrophoretic distribution of isozymes characterizes each species. The hybrid splake, which is produced artificially by fertilizing lake trout eggs with speckled trout sperm, contains nine isozymes. This comnplement of isozymeg In vivo could be produced in vitro by recombination of subunits from tissues of the parent species. In the splake trout, this complement is the result of heterozygosity at the gene locus responsible for synthesis of LDH-5. Extracts of trout eyes contain at least two additional forms of LDH which could not be demonstrated in other tissues.