Protein kinase isolation

A partially purified cyclic GMP-activated protein kinase from lobster muscle was later found to have a for cyclic GMP of about 0.08 /x.M and for cyclic AMP of about 4 /aM. A cyclic AMP-activated protein kinase isolated from the same tissue had an apparent Ka for cyclic AMP of about 0.02 /J.M and for cyclic GMP of about 1.2 ptM [76]. Cyclic GMP-dependent phosphorylation of endogenous protein has been demonstrated in membranes of mammalian smooth muscle [78]. In the presence of 10 mM Mn, a half-maximal increase in the phosphorylation of these proteins occurred with 20-30 nM cyclic GMP, but ten-fold higher concentrations of cyclic AMP were required to produce the same increase in phosphorylation. 

Garbers, D.L., First, N.L., and Lardy, H.A, (1973). Properties of adenosine 3, 5 -monophosphate-dependent protein kinases isolated from bovine epididymal spermatozoa. J.BioI.Chem. 248 875-879. 

The tjipanazoles (18, 19a-d, 20a-b) a group of A-glycosides of indolo-[2,3-a]carbazole, have been isolated from the moderately antifungal extract of the blue-green alga Tolypothrix tjipanasensis. These alkaloids do not exhibit antitumor or protein kinase C (PKC) inhibitory activity, which is in contrast with the... 

Batcho indole synthesis is a useful tool for synthesis of naniral products. As oudined in Scheme 10.6, the Batcho indole synthesis is used for total synthesis of the slime mold alkaloid arcyriacyanin. Such indolocarbazole alkaloids represent a growing number of naniral products isolated from soil organism, slime molds, and marine sources. They are important as andnimor compounds and protein kinase C and topoisomerase inhibitors. 

The general picture of muscle contraction in the heart resembles that of skeletal muscle. Cardiac muscle, like skeletal muscle, is striated and uses the actin-myosin-tropomyosin-troponin system described above. Unlike skeletal muscle, cardiac muscle exhibits intrinsic rhyth-micity, and individual myocytes communicate with each other because of its syncytial nature. The T tubular system is more developed in cardiac muscle, whereas the sarcoplasmic reticulum is less extensive and consequently the intracellular supply of Ca for contraction is less. Cardiac muscle thus relies on extracellular Ca for contraction if isolated cardiac muscle is deprived of Ca, it ceases to beat within approximately 1 minute, whereas skeletal muscle can continue to contract without an extraceUular source of Ca +. Cyclic AMP plays a more prominent role in cardiac than in skeletal muscle. It modulates intracellular levels of Ca through the activation of protein kinases these enzymes phosphorylate various transport proteins in the sarcolemma and sarcoplasmic reticulum and also in the troponin-tropomyosin regulatory complex, affecting intracellular levels of Ca or responses to it. There is a rough correlation between the phosphorylation of Tpl and the increased contraction of cardiac muscle induced by catecholamines. This may account for the inotropic effects (increased contractility) of P-adrenergic compounds on the heart. Some differences among skeletal, cardiac, and smooth muscle are summarized in... 

Staudinger, J., Zhou, J., Burgess, R., Elledge, S. J., and Olson, E. N. (1995) PICK1 a perinuclear binding protein and substrate for protein kinase C isolated by the yeast two-hybrid... 

Protein isolation, by conjugating, 13 748 Protein kinases, 20 832 Protein metabolism, anabolic steroids and, 13 5-6... 

A calpain inhibitor, the DPK of N-dimethyltyrosine, was isolated from Streptomyces griseus and this compound showed activity in the calpain assay as described by Alvarez etal Calpain is a cytosolic protease regulated by calcium and is distributed in mammalian and avian cells. Calpain catalyzes proteolysis of target protein in cells, causing changes in metabolic processes such as the activation of protein kinase C, neuropeptide metabolism, and the activation of platelets. It is proposed that these inhibitors can be used in the treatment of neurodegen-erative diseases. 

Carey I, Noti JD (1999) Isolation of protein kinase C-alpha-reguIated cDNAs associated with breast tumor aggressiveness by differentia mRNA display. Int J Oncol 14 951-956... 

McConkey DJ, Hartzell P, Jondal M, Orrenius S (1989) Inhibition of DNA fragmentation in thymocytes and isolated thymocyte nuclei by agents that simulate protein kinase C.) Biol Chem 264 13399-13402 McConkey DJ, Nicotera P, Orrenius S (1994) Signalling and chromatin fragmentation in thymocyte apoptosis. Immunol Rev 142 343-363 McCoy C, Smith DE, Cornwell MM (1995) 12-0-tetradecanoylphorbol-13-acetate activation of the MDRl promoter is mediated by EGRl. Mol Cell Biol 15 6100-6108... 

Sanchez V, Lucas M, Sanz A, Goberna R (1992) Decreased protein kinase C activity is associated with programmed cell death (apoptosis) in freshly isolated rat hepato-cytes. Biosci Rep 12 199-206... 

The majority of indolocarbazole alkaloids, isolated so far from nature, are derivatives of the indolo[2,3-fl]pyrrolo[3,4-c]carbazole ring system 292. They have been isolated from soil organisms, slime molds, and marine sources (3,7,8,252-255), and have shown a broad range of potent biological activities, such as antifungal, antimicrobial, antitumor, and antihypertensive activity (3,7,256-260,267-270). Their activity as potent inhibitors of protein kinase C (PKC) has received special attention, and was the focus of several investigations (8,257,258,271-280). The history of these natural products dates back about 30 years (Scheme 2.73). 

Since the first isolation and the discovery of the potent inhibitory activity of the microbial alkaloid staurosporine (295) against protein kinase C (PKC), the indolo[2,3-fl] carbazole alkaloids have emerged as a rapidly growing family. This was attested to by the isolation of about 70 natural products. In addition to this large... 

The phosphorylation of proteins on Ser, Thr or Tyr residues is a basic tool for the regulation of protein activity (see 7.1). Many eucaryotic transcriptional activators are isolated as phosphorylated proteins. The phosphorylation occurrs mainly on the Ser and Thr residues, but can also be observed on the Tyr residues. The extent of phosphorylation is regulated via specific protein kinases and protein phosphatases, each components of signal transduction pathways (see ch. 7). The phosphorylation of transcriptio-... 

Ahn, ., M. Hahm, E. Park, and H. Lee. 1998. Corosolic acid isolated from the fruit of Crataegus pinnatifida var. psilosa is a protein kinase C inhibitor as well as a cytotoxic agent. Planta Med. 64 468-470. 

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