The first description of a saturable iminodipeptide transport system present in human erythrocytes is given. The 1H-n.m.r. spectra of glycyl-L-proline and those of free glycine and L-proline are significantly different. This enabled the non-invasive monitoring by 1H-n.m.r. spectroscopy of the hydrolysis of the dipeptide in human erythrocytes and their lysates. The concentration-dependence of th...

Yeast polygalacturonase catalyzes a random hydrolysis of pectic acid to a mixture of digalacturonic and galacturonic acids via a series of oligogalacturonides (1). This enzyme will be termed yeast endo-polygalacturonase to differentiate it from end group-hydrolyzing enzymes, which have been named exopolygalacturonases (2). Evidence has been presented that yeast endo-polygalacturonase is a singl...

The hydrolysis of potassium organotrifluoroborate (RBF(3)K) reagents to the corresponding boronic acids (RB(OH)(2)) has been studied in the context of their application in Suzuki-Miyaura coupling. The "slow release" strategy in such SM couplings is only viable if there is an appropriate gearing of the hydrolysis rate of the RBF(3)K reagent with the rate of catalytic turnover. In such cases, the...

Phosphodiester linkages, including those that join the nucleotides of DNA, are highly resistant to spontaneous hydrolysis. The rate of water attack at the phosphorus atom of phosphodiesters is known only as an upper limit, based on the hydrolysis of the dimethyl phosphate anion. That reaction was found to proceed at least 99% by C-O cleavage, at a rate suggesting an upper limit of 10(-15) s(-1)...

Whereas ATPgammaS is often considered a nonhydrolyzable substrate for ATPases, we present evidence that ATPgammaS is a good substrate for the RNA-stimulated nucleotide hydrolysis and RNA unwinding activities of eIF4A. In the presence of saturating single-stranded poly(U) RNA, eIF4A hydrolyzes ATPgammaS.Mg and ATP.Mg with similar steady-state parameters (KM(NTP.Mg) = 66 and 58 microM and kcat = ...

daily, organophosphorus compounds (ops) in human life, has found wide applications. although ops have biodegradability potential, they induce clinical problems in humans and other organism. different methods are used to detoxify these compounds. in the meantime, biodegradation is preferred as a compatible way to the environment since it produces less toxic compounds. enzymes capable to degrade ...

cow’s milk whey consists of many protein components and some of them are antigens to human and known to modulate immune responses. enzymatic hydrolysis is a useful method to modify proteins with allergenicity. the objective of this study was to identify whether the in vitro enzymatic hydrolysis could reduce the allergenicity of whey protein concentrates (wpc). in  this study, wpc were hydrolyze...

The theory of elastic group transfer for the binding and release rate constants for nucleotides in F1-ATPase as a function of the rotor angle is further extended in several respects. (i) A method is described for predicting the experimentally observed lifetime distribution of long binding events in the controlled rotation experiments by taking into account the hydrolysis and synthesis reactions...

Vaccinia topoisomerase forms a covalent protein-DNA intermediate at sites containing the sequence 5'-CCCTT. The T nucleotide is linked via a 3'-phosphodiester bond to Tyr-274 of the enzyme. Here, we report that the enzyme catalyzes hydrolysis of the covalent intermediate, resulting in formation of a 3'-phosphate-terminated DNA cleavage product. The hydrolysis reaction is pH-dependent (optimum p...