A cytosolic sialic acid-specific O-acetyl-esterase was previously described that can remove O-acetyl esters from the 9-position of sialic acids. We show that rat liver Golgi vesicles contain a distinct sialic acid-esterase located within the lumen of the same vesicles that add O-acetyl esters to sialic acids. Studies of a retinoblastoma cell line genetically deficient in the cytosolic enzyme al...

PURPOSE To investigate the copaiba oil on the hepatic damage induced by acetaminophen, comparing against corn oil. METHODS Fifty four rats were distributed into nine study groups (N=6): control group, that didn't receive the acetaminophen; Acetaminophen Group, that only received the acetaminophen; Prophylactic Copaiba Group 1, that received copaiba oil two hours before the acetaminophen; Prop...

Batch hydrolysis kinetics of paper birch (Betula papyrifera) xylan and its associated acetyl groups in dilute sulfuric acid have been measured for acid concentrations of between 0.04 and 0.18M and temperatures of between 100 and 170 degrees C. Only 5% of the cellulose was hydrolyzed for up to 85% xylan removal. Rate data were correlated well by a parallel reaction model based on the existence o...

Synthesis of partially 2'/3'-O-acetylated oligoribonucleotides has been accomplished by using a 2'/3'-O-acetyl orthogonal protecting group strategy in which non-nucleophilic strong-base (DBU) labile nucleobase protecting groups and a UV-light cleavable linker were used. Strong-base stability of the photolabile linker allowed on-column nucleobase and phosphate deprotection, followed by a mild cl...

Cells sense and appropriately respond to the physical conditions and availability of nutrients in their environment. This sensing of the environment and consequent cellular responses are orchestrated by a multitude of signaling pathways and typically involve changes in transcription and metabolism. Recent discoveries suggest that the signaling and transcription machineries are regulated by sign...

We have presented evidence that stimulation of pyruvate dehydrogenase, (PDH.) kinase activity by pyruvate or by acetyl-CoA is mediated through acetylation of lipoyl moieties (Cate, R. L., and Roche, T. E. (1978) J. Biol. Chem. 253,496-503). In accord with this indirect mechanism for the action of these effecters, we now find that the degree of stimulation of PDH, kinase increases with the level...

The selective transformation of chitin into various renewable N-containing chemicals and medicines has attracted increasing attention. However, the N-acetyl groups in construct strong hydrogen bond networks, which restricts its depolymerization transformation. conversion robust commonly requires considerable base catalysts to remove group as a byproduct advance, is non-compliance with principle...

lead is a common toxic agent which impairs various organs functions of the body. the basis of this toxicity is believed to be the negative influence on enzymatic system of cells. in the past few years, increasing consideration has been given to interactions occurring between lead and some essential metals including se and zn. based on the finding that some trace elements could reverse the toxic...