Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Replication of bovine papilloma virus (BPV) DNA requires two virus-encoded proteins, E1 and E2, while all other proteins are supplied by the host cell. Here, we describe the isolation of the E1 protein and show that it is a multifunctional protein. Purified E1 protein was required for the in vitro replication of BPV origin-containing DNA by extracts of mouse cells, as reported [Yang, L., Li, R., Mohr, I. J., Clark, R. & Botchan, M. R. (1991) Nature (London) 353, 628-632]. In addition, the E1 protein cosedimented with a number of other activities including (i) DNA helicase activity, (ii) BPV origin-containing DNA-specific binding activity, (iii) DNA-dependent ATPase activity, and (iv) BPV origin-specific unwinding of superhelical DNA. The E1 protein, acting as a helicase, moved in the 3'-->5' direction, like simian virus 40 (SV40) large tumor antigen, which plays a pivotal role in SV40 DNA replication. However, unlike the SV40 large tumor antigen, the helicase activity of E1 was stimulated 5-fold by the presence of a fork structure at the junction between single-stranded and double-stranded DNA and was supported efficiently by all eight nucleoside triphosphates. The E1-catalyzed ATPase activity required the presence of single-stranded or double-stranded DNAs.
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PMID:Bovine papilloma virus (BPV)-encoded E1 protein contains multiple activities required for BPV DNA replication. 838 Jun 45

IL-1beta is suspected to be involved in the diarrhea that always accompanies inflammatory bowel disease. This work was aimed at studying the in vivo effect of IL-1beta on the net absorption of fluid, Na(+) and Cl(-) from the rat colon, and at delineating its mechanism of action. Rats were injected i.p. with IL-1beta (1 mug/kg body weight) and the colon was perfused, four hours later, with Krebs-Ringer buffer. Net fluid absorption was calculated as the difference between the total volume of the buffer infused and collected per cm(2) of perfused intestine. Chloride in both buffers was determined by titration according to Mohr's method and net Cl- absorption was calculated in the same way. IL-1beta reduced the net absorption of water and chloride. The cytokine also reduced the percentage recovery of the Na(+)-K(+) ATPase activity in crude homogenates of membranes from surface and crypt colonic cells as revealed by the determination of inorganic phosphate released. In addition IL-1beta decreased the protein expression of the Na(+)-K(+) pump and increased that of the NaKCl(2) symporter. It is concluded that IL-1beta has a dual effect: it inhibits the Na(+)-K(+) pump and consequently NaCl absorption, and up-regulates the NaKCl(2) transporter and increases Cl(-) secretion. The ultimate effect of the two processes is a net decrease in Na(+)+ and Cl(-) absorption and an increase in water retention in the colon leading to the observed diarrhea in inflammatory bowel disease.
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PMID:The mechanism by which interleukin-1 beta reduces net fluid absorption from the rat colon. 1223 80