Journal ArticleDOI
The effect of quercetin on the phosphorylatio activity of the Rous sarcoma virus transforming gene product in vitro and in vivo
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The phosphotransferase activity of the Rous sarcoma virus src gene product, pp60src, was inhibited both in vitro and in vivo by the bioflavonoid quercetin and studies in vitro showed that this flavonoid did not inhibit the phosphorylation of physiological substrates of this enzyme.Abstract:
The phosphotransferase activity of the Rous sarcoma virus src gene product, pp60src, was inhibited both in vitro and in vivo by the bioflavonoid quercetin. The Ki for the inhibitory effect was in the range of 6-11 microM under conditions in vitro. The inhibitory effect of quercetin was competitive towards the nucleotides ATP and GTP as substrates for pp60src and was non-competitive towards alpha-casein as the protein substrate of this kinase activity. In contrast, studies in vitro of the phosphotransferase activity of the catalytic subunit of the cAMP-dependent protein kinase showed that this flavonoid did not inhibit the phosphorylation of physiological substrates of this enzyme. In cultured cells the half-maximal inhibition of tyrosine phosphorylation of pp60src as well as the phosphorylation of the Mr = 34000 protein, a physiological substrate of pp60src, was in the range 0.06-0.08 mM.read more
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The Effects of Plant Flavonoids on Mammalian Cells:Implications for Inflammation, Heart Disease, and Cancer
TL;DR: Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional, and suggestions are made where such possibilities may be worth pursuing.
Journal ArticleDOI
Genistein, a specific inhibitor of tyrosine-specific protein kinases.
Tetsu Akiyama,J Ishida,Shinsaku Nakagawa,Hiroshi Ogawara,Shinya Watanabe,N Itoh,M Shibuya,Yasuo Fukami +7 more
TL;DR: Genistein inhibited the EGF-stimulated increase in phosphotyrosine level in A431 cells and scarcely inhibited the enzyme activities of serine- and threonine-specific protein kinases such as cAMP-dependent protein kinase, phosphorylase kinases, and the Ca2+/phospholipid-dependent enzymeprotein kinase C.
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A specific inhibitor of phosphatidylinositol 3-kinase, 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002).
TL;DR: One such compound, 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one, LY294002, completely and specifically abolished PtdIns 3-kinase activity, which may be beneficial in the treatment of proliferative diseases as well as in elucidating the biological role of the kinase in cellular proliferation and growth factor response.
Journal ArticleDOI
The biochemistry and medical significance of the flavonoids.
TL;DR: Flavonoids are plant pigments that are synthesised from phenylalanine, generally display marvelous colors known from flower petals, mostly emit brilliant fluorescence when they are excited by UV light, and are ubiquitous to green plant cells.
Journal ArticleDOI
Tyrosine kinase inhibition: an approach to drug development
Alexander Levitzki,Aviv Gazit +1 more
TL;DR: This article summarizes recent progress in the development of PTK inhibitors and demonstrates their potential use in the treatment of disease.
References
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Journal ArticleDOI
Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4
TL;DR: Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products.
Journal Article
Cleavage of structural proteins during the assemble of the head of bacterio-phage T4
TL;DR: Using an improved method of gel electrophoresis, many hitherto unknown proteins have been found in bacteriophage T4 and some of these have been identified with specific gene products as mentioned in this paper.
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Journal ArticleDOI
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TL;DR: A rapid and convenient method for peptide mapping of proteins has been developed that involves partial enzymatic proteolysis in the presence of sodium dodecyl sulfate and analysis of the cleavage products by polyacrylamide gel electrophoresis.