Enzyme Assays

Publication Title: 
Nature

The lengths of human telomeres, which protect chromosome ends from degradation and end fusions, are crucial determinants of cell lifespan. During embryogenesis and in cancer, the telomerase enzyme counteracts telomeric DNA shortening. As shown in cancer cells, human telomerase binds the shelterin component TPP1 at telomeres during the S phase of the cell cycle, and adds ~60 nucleotides in a single round of extension, after which telomerase is turned off by unknown mechanisms.

Author(s): 
Chen, Liuh-Yow
Redon, Sophie
Lingner, Joachim
Publication Title: 
Nature

The lengths of human telomeres, which protect chromosome ends from degradation and end fusions, are crucial determinants of cell lifespan. During embryogenesis and in cancer, the telomerase enzyme counteracts telomeric DNA shortening. As shown in cancer cells, human telomerase binds the shelterin component TPP1 at telomeres during the S phase of the cell cycle, and adds ~60 nucleotides in a single round of extension, after which telomerase is turned off by unknown mechanisms.

Author(s): 
Chen, Liuh-Yow
Redon, Sophie
Lingner, Joachim
Publication Title: 
Biochemical and Biophysical Research Communications

Cellular senescence is a tumor suppression mechanism. We previously reported that CKII downregulation induces senescence in human lung fibroblast IMR-90 and colon cancer HCT116 cells. In this study, potential longevity drugs, including rapamycin, vitamin C, and vitamin E, blocked CKII downregulation-mediated senescence through reduction of reactive oxygen species (ROS) production in HCT116 cells.

Author(s): 
Park, Ji Hye
Kim, Jin Joo
Bae, Young-Seuk
Publication Title: 
Methods in Molecular Biology (Clifton, N.J.)

Helicobacter pylori is a Gram-negative bacteria that infects the human stomach of half of the world's -population. Colonization is followed by infiltration of the gastric mucosa by lymphocytes and myeloid cells. These cells are activated by various bacterial factors, causing them to produce immune/inflammatory mediators, including reactive nitrogen species and polyamines that contribute to cellular damage and the pathogenesis of H. pylori-associated gastric cancer. In vitro experiments have revealed that H.

Author(s): 
Gobert, Alain P.
Chaturvedi, Rupesh
Wilson, Keith T.
Publication Title: 
The Journal of Pharmacology and Experimental Therapeutics

Prostaglandins (PGs) are a family of cellular messengers exerting diverse homeostatic and pathophysiologic effects. Recently, several studies reported significant increases of PGI(2) and PGF(2α) after the inhibition of microsomal PGE synthase-1 (mPGES-1) expression, which indicated that PGH(2) metabolism might be redistributed when the PGE(2) pathway is blocked.

Author(s): 
Yu, Rui
Xiao, Lei
Zhao, Guiqing
Christman, John W.
van Breemen, Richard B.
Publication Title: 
Analytical Biochemistry

A simple off-column capillary electrophoretic (CE) assay for measuring acetyl coenzyme A carboxylase holoenzyme (holo-ACC) activity and inhibition was developed. The two reactions catalyzed by the holo-ACC components, biotin carboxylase (BC) and carboxyltransferase (CT), were simultaneously monitored in this assay. Acetyl coenzyme A (CoA), malonyl-CoA, adenosine triphosphate (ATP), and adenosine diphosphate (ADP) were separated by capillary electrophoresis, and the depletion of ATP and acetyl-CoA as well as the production of ADP and malonyl-CoA were monitored.

Author(s): 
Bryant, Sherrisse K.
Waldrop, Grover L.
Gilman, S. Douglass
Publication Title: 
Molecules (Basel, Switzerland)

Murraya koenigii is an edible herb widely used in folk medicine. Here we report that girinimbine, a carbazole alkaloid isolated from this plant, inhibited the growth and induced apoptosis in human hepatocellular carcinoma, HepG2 cells. The MTT and LDH assay results showed that girinimbine decreased cell viability and increased cytotoxicity in a dose-and time-dependent manner selectively. Girinimbine-treated HepG2 cells showed typical morphological features of apoptosis, as observed from normal inverted microscopy and Hoechst 33342 assay.

Author(s): 
Syam, Suvitha
Abdul, Ahmad Bustamam
Sukari, Mohd Aspollah
Mohan, Syam
Abdelwahab, Siddig Ibrahim
Wah, Tang Sook
Publication Title: 
Molecules (Basel, Switzerland)

Inonotus obliquus is a medicinal mushroom used in Russian and Eastern European folk medicine for the treatment of gastrointestinal cancer, cardiovascular disease and diabetes. Previous studies in our laboratory have demonstrated that the mycelium powders of I. obliquus possess significant antihyperglycemic effects in a mouse model of diabetic disease induced by alloxan. However, the active ingredients of mycelium powders responsible for the diabetes activity have not been identified. This study aims to identify the active ingredients of I.

Author(s): 
Geng, Yan
Lu, Zhen-Ming
Huang, Wei
Xu, Hong-Yu
Shi, Jin-Song
Xu, Zheng-Hong
Publication Title: 
Photosynthesis Research

Rubisco frequently undergoes unproductive interactions with its sugar-phosphate substrate that stabilize active sites in an inactive conformation. Restoring catalytic competence to these sites requires the "molecular chiropractic" activity of Rubisco activase (activase). To make the study of activase more routine and physiologically relevant, an assay was devised for measuring activase activity in leaf extracts based on the ATP-dependent activation of inactive Rubisco.

Author(s): 
Carmo-Silva, A. Elizabete
Salvucci, Michael E.
Publication Title: 
PloS One

To pursue a systematic approach to discovery of mechanisms of action of traditional Chinese medicine (TCM), we used microarrays, bioinformatics and the "Connectivity Map" (CMAP) to examine TCM-induced changes in gene expression. We demonstrated that this approach can be used to elucidate new molecular targets using a model TCM herbal formula Si-Wu-Tang (SWT) which is widely used for women's health.

Author(s): 
Wen, Zhining
Wang, Zhijun
Wang, Steven
Ravula, Ranadheer
Yang, Lun
Xu, Jun
Wang, Charles
Zuo, Zhong
Chow, Moses S. S.
Shi, Leming
Huang, Ying
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