Lactate dehydrogenase isozymes in human cardiac transplantation

Lactate dehydrogenase (LDH) isozyme activities have been followed in 17 human cardiac allografts. A pattern of abnormality associated with cardiac rejection during the first month after operation has been determined: (i) LDH-1 activity is greater than LDH-2 activity; (ii) LDH-1 activity is greater than 35 percent of total LDH activity; and (iii) LDH-1 activity is greater than 100 international units. The LDH-1 abnormality helps to meet the need for an index of cardiac rejection during the early weeks after operation when the electro-cardiogram is least reliable.     

Lactate Dehydrogenase Isozymes: Dissociation and Recombination of Subunits

Lactate dehydrogenase from beef tissues may be resolved electrophoretically into five isozymes each of which is a tetramer. These tetramers can be dissociated into monomers by freezing in 1M sodium chloride. On thawing, reassociation into functional tetramers occurs. On the basis of charge and amino acid composition there are two kinds of monomers. Lactate dehydrogenase-1 contains one kind of monomer and lactate dehydrogenase-5 the other kind. A mixture of equal quantities of these two isozymes, after dissociation and reassociation, leads to the production of all five isozymes in the expected proportions of 1:4:6:4:1.     

Lactate dehydrogenase variant from human blood: evidence for molecular subunits

A variant of human lactate dehydrogenase is described. The occurrence of lactate dehydrogenase-1, -2, -3, and -4 as five, four, three, and two components, respectively, is interpreted as supporting the hypothesis that LDH isozymes are tetramers formed from various combinations of two types of subunits.     

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.     

中国林蛙六种组织乳酸脱氢酶同工酶的研究

本文应用聚丙烯酰胺凝胶电泳结合光密度扫描的方法,对中国林蛙6种组织器官的乳酸脱氢酶(LDH)同工酶进行分析研究,结果表明:存在3种基因(Ldh-A、-B、-C)编码的LDH 同工酶;在不同组织中 LDH 同工酶差异显著,其中心肌以 LDH_2、LDH_1活性最高,骨骼肌、肝脏以及脑组织以 LDH_5活性最高,LDHc 仅出现在肝脏及骨骼肌中。     

Lactate dehydrogenase isozymes: dissociation and denaturation by dilution

The tetrameric enzyme lactate dehydrogenase dissociates into its constituent monomeric subunits in a high ion to protein concentration ratio, in certain ionic environments when frozen, and at extreme dilution. Dissociation by dilution involves changes in tertiary conformation which inactivate the enzyme. The dissociation is strongly inhibited by homologous native proteins, but only slightly by denatured or unrelated proteins.     

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.     

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.     

Lactate dehydrogenase isozymes: further kinetic studies at high enzyme concentration

In the report "Lactate dehydrogenase isozymes: Further kinetic studies at high enzyme concentration" by Thomas Wuntsch, Raymond F. Chen, and Elliot S. Vesell [169, 480 (1970)], 14.0 mM NAD in line 2 of the heading of Table 1 should read 14.0 , microM NAD.     

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.     

Lactate dehydrogenase: An important molecule involved in acetamizuril action against Eimeria tenella

Lactate dehydrogenase(LDH), a vital enzyme in anaerobic glycolysis, is closely associated with the survival of parasites. Previous studies of some parasites have shown that LDH exhibits unique physicochemical properties and molecular structures and may be an ideal potential target for diagnosis and drug screening. In this study, we aimed to investigate the effects of acetamizuril, a novel anticoccidial compound, on LDH in the second-generation merozoites of Eimeria tenella(mz-LDH). Quantitative real-time PCR, Western blot, immunofluorescence and enzyme activity assays were each applied to detect the changes of mz-LDH. Our results indicated that the mRNA and protein levels of mz-LDH were reduced upon acetamizuril treatment. Immunolocalization of mz-LDH demonstrated that considerable amount of mz-LDH was distributed around or in the nuclei of second-generation merozoites within the untreated group; in contrast, the acetamizuril-treated group had very low level of mz-LDH. Meanwhile, LDH enzyme activity assay suggested that a decreased LDH enzyme activity in both cytoplasm and nucleus of merozoites in the acetamizuril-treated group. Moreover, the induced apoptosis in second-generation merozoites by the acetamizuril was evaluated by detecting caspase 3 activity, and acetamizuril was found to significantly increase caspase 3 activity. The above findings show that LDH may play an important role in the mediating the activity of acetamizuril against coccidiosis, and further investigation into this aspect might contribute to new light on the pathogenesis of E. tenella during its interaction with acetamizuril.     

Lactate dehydrogenase electrophoretic variant in a New Guinea Highland population

Six examples of a variation in the LDH-A subunit have been detected in 408 samples from three exogamous clans in the New Guinea Highlands. The New Guinea variant is similar to the Memphis-4 variant. Origin of the New Guinea variant could not be traced by genealogy but it seems likely to have persisted for several generations.     

Lactate dehydrogenase isozymes in parthenogenetic teiid lizards (Cnemidophorus)

Heterozygosity occurs at the lactate dehydrogenase b-locus in two diploid parthenogenetic species of Cnemidophorus. Each such species produces two different B subunits, one of which is also found in two sexual species and in two triploid parthenogenetic species; the other occurs also in a third sexual species. Interspecific hybridization between sexual species carrying different b-alleles and producing different B subunits may be responsible for the heterozygosity at the lactate dehydrogenase b-locus in diploid parthenogenetic Cnemidophours.     

塔里木河大狗头鱼乳酸脱氢酶（LDH）同工酶凝胶电泳分析

本实验用聚丙烯酸胺凝胶电泳（PAGE）方法,对塔里木河大狗头鱼（学名：叶尔羌鼓鳔鳅）六种不同组织（骨骼肌、心、肝胰、肾、肠、鳃）中LDH同工酶进行了分析研究,结果表明,LDH同工酶具有组织特异性,其中骨骼肌中含有五种LDH同工酶,即LDH1、LDH2、LDH3、LDH4、LDH5,心、肝胰和肾含有LDH1、LDH2、LDH3,鳃有LDH1和LDH4,肠有LDH4。     

Lactate dehydrogenase isozymes of chick embryo: response to variations of ambient oxygen tension

Incubation of chick embryos in an hypoxic environment causes an ncrease in the proportion of tissue lactate dehydrogenase (LDH) made up of subunit M, whereas incubation in aerobic conditions decreases the proportional amount of subunit M. The variation of ambient oxygen tension does not change the total LDH activity. These results support the hypothesis that oxygen or oxidative metabolites have an effect on the synthesis of the subunit peptides.     

Alpha-glycerophosphate dehydrogenase and glucose-6-phosphate dehydrogenase in tissues of the Weddell seal

High activity of alpha-glycerophosphate dehydrogenase and low activity of glucose-6-phosphate dehydrogenase in adipose tissue of Weddell seals suggest that neutral fat may be assembled there from exogenous sources of fatty acids. Low activity of glucose-6-phosphate dehydrogenase in other tissues tested precludes assignment of the function of fatty-acid synthesis to any specific tissue and emphasizes uniqueness of adipose mass in seals.     

Location of the c-yes gene on the human chromosome and its expression in various tissues

Analysis of DNA from human embryo fibroblasts showed that ten Eco RI fragments were hybridizable with the Yamaguchi sarcoma virus oncogene (v-yes). Four of the Eco RI fragments were assigned to chromosome 18 and one to chromosome 6. There was evidence for multiple copies of yes-related genes in the human genome; however, only a single RNA species, 4.8 kilobases in length, was related to yes in various cells.     

大口黑鲈形态特征、染色体核型及眼晶状体乳酸脱氢酶的电泳分析

旨在了解大口黑鲈(Micropterus salmoides )的种质特性,为其种质鉴定提供理论依据。采用传统形态学方法观测样品形态特征,借助肾细胞滴片空气干燥法制备染色体标本并进行核型分析,通过聚丙烯酰胺凝胶电泳法研究大口黑鲈眼晶状体乳酸脱氢酶(LDH)。结果表明：大口黑鲈体呈纺锤形,口裂大,斜裂;背部黑绿色,体侧青绿;吻端至尾鳍基部有排列成带状的黑斑。鳃盖上有3条呈放射状的黑斑;背鳍鳍式 D.VIII~XI-11~14;臀鳍鳍式A.III-9~12;左侧第一鳃弓外侧鳃耙数为6~7,鳔1室,脊椎骨总数30~32。染色体数目2n=46,核型公式为2m+2st+42t,臂数NF=48,未发现带有随体、次缢痕的染色体和异型性染色体,大口黑鲈进化上符合高位类群核型特征;眼晶状体中的LDH酶带5条,观察到LDHA、LDHB和LDHC 3个基因位点。综上所述,在对大口黑鲈进行种质鉴定时,建议采用多种种质鉴定技术手段系统化地考察和评价其种质状况。