• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.461-467
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• 1989

The activity of lactate dehydrogenase in plasma and various tissues(skeletal muscle, cardiac muscle, liver, lung, kidney and spleen) of Korean native cattle in a Chonju abattoir, the Breeding Stock Farm and Animal Farm of Chonbuk University was determined by using ultra violet method. Using polyacrylamide gel electrophoresis, the lactate dehydrogenase isoenzyme distrimution of plasma and various tissues in Korean native cattle was studied. The plasma lactate dehydrogenase activity of Korean native cattle was $554.80{\pm}92.70IU/l$ and the lactate dehydrogenase activity of male plasma was $543.96{\pm}97.89IU/l$, which was lower than that of female plasma, $579.19{\pm}78.09IU/l$. The plasma lactate dehydrogenase activity of calf was $557.31{\pm}110.27IU/l$ and was no significantly different from that of adult Korean native cattle. But the range of calf lactate dehydrogenase activity was larger than that of adult Korean native cattle. In tissues, the lactate dehydrogenase activity was decreased in order of lung, kidney, spleen, liver, heart and skeletal muscle. The lung had the greatest activity and the skeletal muscle had the least. Lactate dehydrogenase isoenzymes in plasma and tissues were found to have a characteristic distribution and quantitative isoenzyme patterns. In plasma, the LDH1 usually had the greatest activity and other isoenzymes showed a decreasing tendency in order of LDH2, LDH3, LDH4 and LDH5. The distribution of lactate dehydrogenase isoenzymes had a wide variation in tissues. But the distribution of LDH isoenzymes in plasma was similar to that in kidney, and also cardiac muscle and spleen had similar pattern in LDH isoenzymes distribution.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.318-322
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• 2004

Lactic acid is an environmentally benign organic acid that could be used as a raw material for biodegradable plastics if it can be inexpensively produced by fermentation. Two genes (ldhL and ldhD) encoding the L-(+) and D-(-) lactate dehydrogenases (L-LDH and D-LDH) were cloned from Lactobacillus sp., RKY2, which is a lactic acid hyper-producing bacterium isolated from Kimchi. Open reading frames of ldhL for and ldhD for the L and D-LDH genes were 962 and 998 bp, respectively. Both the L(+)- and D(-)-LDH proteins showed the highest degree of homology with the L- and D-lactate dehydrogenase genes of Lactobacillus plantarum. The conserved residues in the catalytic activity and substrate binding of both LDHs were identified in both enzymes.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.213-218
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• 2010

Lactate dehydrogenases (LDHs) have been highly focused for long time, due to their important roles in biochemical and metabolic pathways of cells. On the basis of genome-wide searching results, three putative LDH genes from Bacillus cereus ATCC 14579 genome have been PCR-amplified, cloned, and well-expressed in E. coli. All three BcLDH isozymes are supposed to share highly conserved catalytic amino acid residues in common $NAD^+$-dependent LDHs. Meanwhile, BcLDH1 consisting of 314 amino acids shares 86 and 49% of identities with BcLDH2 and 3, respectively. Interestingly, only BcLDH1 showed the converting activities between L-lactate and pyruvate in the presence of $NAD^+$ coenzyme, while the other isozymes are likely to have almost no activity. As a result, it was revealed that BcLDH1 can be a typical $NAD^+$-dependent L-lactate-specific dehydrogenase.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.716-721
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• 2002

The ldhL gene encoding the $_L$-(+) lactate dehydrogenase was cloned from Lactobacillus reuteri ATCC 55739 chromosomal DNA and characterized. An internal 750-bp fiagment of ldhL gene was amplified by PCR using primers based on the conserved region of lactobacilli ldhL genes. A genomic library off. reuteri ATCC 55739 was constructed using pBR322, and colony hybridization experiments were performed using the 750-bp fragment as aprobe. One clone harboring a 4.0-kb PstI fragment was identified, and nucleotide sequencing confirmed it as an open reading frame of 972 bp in size in the middle. In addition to IdhL gene, an ORF homologous to Streptococcus pneumoniae TIGR4 hydrolase gene and 3' part of phosphomevalonate kinase gene (mvaK2) were also found on the 4 kb fragment. $_L$-LDH of L. reuteri ATCC 55739 showed the highest degree of homology with the $_L$-LDH of Pediococcus acidilactici (62.4%), fullowed by the $_L$-LDH of Lactobacillus pentosus (58.7%). The size of IdhL transcript determined by Northern blot was 1 kb, indicating the monocistronic nature of IdhL.

• Journal of Microbiology and Biotechnology
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• v.25 no.1
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• pp.81-88
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• 2015

This study describes a novel strategy to regulate the metabolic flux for lactic acid production in Lactobacillus casei. The ldhL gene encoding _L-lactate dehydrogenase (L-LDH) was overexpressed in L. casei, and a two-stage oxygen supply strategy (TOS) that maintained a medium oxygen supply level during the early fermentation phase, and a low oxygen supply level in the later phase was carried out. As a consequence, a maximum L-LDH activity of 95.6 U/ml was obtained in the recombinant strain, which was over 4-fold higher than that of the initial strain. Under the TOS for L. casei (pMG-ldhL), the maximum lactic acid concentration of 159.6 g/l was obtained in 36 h, corresponding to a 62.8% increase. The results presented here provide a novel way to regulate the metabolic flux of L. casei for lactic acid production in different fermentation stages, which is available to enhance organic acid production in other strains.

• Biomedical Science Letters
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• v.27 no.3
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• pp.170-176
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• 2021

Thapsigargin (TG), a sarco/endoplasmic reticulum (ER) Ca²⁺-ATPase (SERCA) inhibitor, has been widely used as an agonist for platelet aggregation for decades. In this study, we investigated the effect of TG on the release of lactate dehydrogenase (LDH) for platelets and elucidated its mechanism. Platelet LDH release and platelet aggregation were increased by TG treatment; 1,000 nM of TG induced the complete lysis of platelets. Other agonists such as collagen (2.5 ㎍/mL), thrombin (0.1 U/mL), and ADP (10 mM) did not induce significant platelet LDH release despite platelet aggregation. Finally, we investigated the effects of pharmacological inhibitors on TG-induced platelet aggregation and LDH release. SP600125, a JNK inhibitor, and LY294002, a PI-3K inhibitor, inhibited TG-induced platelet LDH release but not platelet aggregation. Forskolin, an adenylyl cyclase activator, also inhibited LDH release without affecting platelet aggregation by TG. These results suggest that the TG-induced platelet aggregation was accompanied by LDH release but regulated by a different signaling pathway.

• Journal of Life Science
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• v.14 no.4
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• pp.708-715
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• 2004

The lactate dehydrogenase (EC 1.1.1.27, LDH) in liver of Lempetra japonica was purified in buffer of affinity chromatography. The liver-specific $C_4$ isozyme of Gadus macrocephalus was purified by heat treatment, affinity chromatography, and DEAE-Sephacel chromatography. The liver-specific $C_4$ isozyme was eluted in a buffer containing NAD+ and was coeluted with $B_4$isozyme in plain buffer of affinity chromagraphy. Liver-specific $C_4$ isozyme in G. macrocephalus was the most thermostable, and$B_4$isozyme was more stable than $A_4$. The LDH in the fraction of pH 7.45 purified from the liver of L. iaponica by chromatofocusing was more inhibited by pyruvate than purified LDH. The optimum pH of the LDH isozyme in the liver of L. japonica was 7.5 and that of liver-specific$C_4$ isozyme was 8.5. The LDH in liver of L. japonica made complexes more with antibody against Coreoperca herzi$A_4$ and liver-specific $C_4$ than with that against eye-specific $C_4$. Therefore, the structure of the LDH in liver of L. japonica might be similarly evolved to that of subunit A and liver-specific $C_4$ isozyme in liver tissue of G. macrocephalus. The evolution rate of subunit C is faster than that of subunit A. LDH in liver of L. japonica has not one isozyme but isozymes and it was also found out to have not only subunit A and B but also subunit C.

• Journal of Life Science
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• v.26 no.2
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• pp.155-163
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• 2016

Metabolism of lactate dehydrogenase (EC 1.1.1.27, LDH) was studied to identify the function of LDH-C. Tissues of LDH liver-specific Ldh-C expressed Carassius auratus and eye-specific Ldh-C expressed Lepomis macrochirus after starvation were studied. LDH activity in liver tissue from C. auratus was increased after starvation. And LDH specific activity (units/mg) and LDH/CS were increased in tissues. It means the anaerobic metabolism was taking place in C. auratus after starvation. LDH B₄ isozyme was decreased in skeletal muscle and increased in heart tissue. LDH C₄ isozymes those showed in eye and brain tissues were identified as liver-specific C₄ isozymes and disappeared after starvation. And C hybrid in eye, A₄ isozyme in brain, and both C hybrid and C₄ isozyme in liver tissue were increased, respectively. In L. macrochirus, the level of variation of LDH activities was low but greatly increased especially in eye tissue and LDH A₄ and AC hybrid were increased in brain tissue. The LDH activities in tissues from C. auratus and L. macrochirus remained 30.30-18.64% and 25-18.75%, respectively, as a result of the inhibition by 10 mM of pyruvate. The Km^PYR values of LDH in C. auratus were increased. As a result, LDH liver-specific C₄ isozyme was expressed in liver, brain and eye tissues during starvation. It seems metabolism of lactate was predominant in brain tissue. After starvation, the liver-specific LDH-C was affected more than eye-specific LDH-C.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.625-634
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• 2004

The objective of this experiment is to study the possibility of lactate dehydrogenase(LDH) enzyme to prevent lactate accumulation in the rumen, For understanding capacity of bacterial LDH in rumen environments, this study was conducted to explore the effects of temperature, pH, VFAs and metal ions on Lactobacillus sp. FFy111-1's LDH activity, and the LDH activation in rumen fluid accumulated lactate. The optimum pH and temperature of LDH were pH 7.5 and 40$^{\circ}C$, respectively. The LDH activity had a good thennostability at range from 30 to 50$^{\circ}C$. The highest pH stability of the enzyme was at ranges from pH 7.0 to 8.0 and the enzyme activities showed above 64% level of non-treated one at pH 6.0 and 6.5. The LDH was inactivated by VFAs treatments but was enhanced by metal ion treatments without NaCl and $CuSO_4$ Especially, the LDH activity was increased to 127% and 124% of its original activity by 2 mM of $BaCl_2$ and $MnSO_4$, addition, respectively. When the acidic rumen fluid was treated by LDH enzyme of Lactobacillus sp. FFy111-1, the lactate concentration in the rumen fluid was lower compared with non-treated rumen fluid(P<0.05). This lactate reduction was resulted from an action of LDH. It was proved by result of purified D,L-LDH addition that showed the lowest lactate concentration among the treatments(P<0.05). Although further investigation of microbial LDH and ruminal lactate is needed, these findings suggest that the bacterial LDH has the potential capability to decrease the lactate accumulated in an acidic rumen fluid. Also, screening of super LDH producing bacteria and technical development for improving enzyme activity in rumen environment are essential keys for practical application.

• The Korean Journal of Zoology
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• v.35 no.1
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• pp.102-106
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• 1992

진도개와 삽사리 혈청 lactate dehydrogenase와 혈청 alkaline phosphatase의 동위효소 및 효소활성도를 분석하였다. 전기영동결과 진도개와 삽사리의 혈청에서는 5두지 종류의 LDH의 동위효소가 모두 확인되었다. LDH의 활성도는 진도개의 경우 522.53 $\pm$ 279.96(U/L)이었고 삽사리는 534.10 $\pm$ 280.35(U/L)이었다. 진도개와 삽사리의 혈청 alkaline phosphatase전기 영동상에서 는 한 종류의 동위효소만 관찰되었고 활성도는 진도개의 경우 7.61 $\pm$ 4.52(K-A unit)였고 삽사리는 10.46 $\pm$ 7. 10(K-A unit) 였다. 삽사리의 ALP 활성도는 연령에 따라 커다란 차이를 나타내었다.