BACKGROUND This study was aimed to identify possible intracellular effectors of the somatostatin (SST) antiproliferative activity, in PCCl3 thyroid cells. METHODS To prove the involvement of r-PTPeta in SST's effect, we studied th proliferative activity of subclones of PCCl3 cells that do or do not express this PTP. RESULTS SST inhibited PCCl3 TSH+insulin-dependent cell proliferation throug...

The substrate specificity and the effects of nucleotides and SH-blocking agents on the p-nitrophenylphosphatase activity of intact Ehrlich ascites tumor cells (EAT) cells were studied. DL-beta-Glycerophosphate, o-phosphoethanolamine, cholinephosphate, glucose-6-phosphate, o-carboxyphenylphosphate,, phosphoenolpyruvate and AMP were not attacked by intact cells. ATP is greater than GTP is greater...

Calcineurin (or PP2B) has been reported to be involved in an array of physiological process in insects, and the calcineurin subunit A (CNA) plays a central role in calcineurin activity. We cloned the CNA gene from Plutella xylostella (PxCNA). This gene contains an ORF of 1488 bp that encodes a 495 amino acid protein, showing 98%, and 80% identities to the CNA of Bombyx mori, and humans respecti...

The effect of trypsin on gastric (H+ + K+)-ATPase and K+-phosphatase was studied. Loss of both enzymic activities was biphasic, consisting of a fast and slow phase. Several peptides were produced from the original 105,000-dalton region of the sodium dodecyl sulfate electrophoretic separation, but only two, 87,000 and 47,000 daltons, were labeled following incubation with [gamma-33P]ATP. After a...

Reactive phosphonates are important probes to target the active site of serine hydrolases, one of the largest and most diverse family of enzymes. Developing such inhibitory probes is of special importance in activity based protein profiling, a strategy that is increasingly used to gain information about a certain class of enzymes in complex proteosomes. Therefore, gaining detailed information a...

SDS, C12E8, CHAPS or CHAPSO or a combination of two of these detergents is generally used for the solubilization of Na,K-ATPase and other ATPases. Our method using only C12E8 has the advantage of considerable reduction of the time for enzyme purification, with rapid solubilization and purification in a single chromatographic step. Na,K-ATPase-rich membrane fragments of rabbit kidney outer medul...

As is often the case with tightly binding inhibitors, okadaic acid produces its inhibitory effect on type 2A protein phosphatase (PP2A) in a time-dependent manner. We measured the rate constants associated with the binding of okadaic acid to PP2A by analysing the time-course of the reduction of the p-nitrophenyl phosphate (pNPP) phosphatase activity of the enzyme after application of okadaic ac...

Coffee wastes have large amounts of by-products rich in phenolic compounds such as chlorogenic and caffeic acid, with potential applications for developing fine chemicals acid phenethyl ester (CAPE). A screening microorganisms was undertaken a coffee plantation environment to isolate native tropical species able modify secondary metabolites present this kind biomass enzymatically. From the scre...