Intramolecular catalysis of phosphate diester hydrolysis. Nucleophilic catalysis by the neighbouring carboxy-group of the hydrolysis of aryl 2-carboxyphenyl phosphates

Khan, Safraz; Kirby, Anthony J.; Wakselman, Michel; Horning, D. P.; Lawlor, J. M.

doi:10.1039/j29700001182

Cited by 31 publications

(27 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both of these enzymes, and many others, use an essential aspartic acid carboxyl function as a nucleophile to form a transient aspartyl phosphate intermediate that is either hydrolysed or donates its phosphoryl group to a second substrate hydroxyl group. [Such covalent activity by a neighbouring carboxyl group was first recognised in model studies of carboxylate mega-activation of phosphonate 29 and phosphate 30 ester hydrolyses in the late 1960s]. In both of these enzymes, our studies have established transition state structures for binary complexes using magnesium trifluoride anion as an isosteric and isoelectronic mimic of the transferring phosphoryl group.…”

Section: Anionic Nucleophile and Anionic Leaving Groupmentioning

confidence: 77%

Why did Nature select phosphate for its dominant roles in biology?

et al. 2010

View full text Add to dashboard Cite

Section: Anionic Nucleophile and Anionic Leaving Groupmentioning

confidence: 77%

Why did Nature select phosphate for its dominant roles in biology?

et al. 2010

View full text Add to dashboard Cite

“…If the subsequent reaction of the dianion does not involve further proton transfer steps, that leads to an expected solvent kinetic isotope effect of approximately 4 due to the reduced concentration of the dianion in D 2 O. The reaction of a fully ionised oxyanion nucleophile with a phosphate diester has only a small secondary solvent isotope effect, which can be slightly inverse (0.8,54 0.9,55 0.9556) or normal (1.1,57 1.558) and the magnitude of this additional effect is consistent with the overall values that we report here 59…”

Section: Resultsmentioning

confidence: 99%

Overcoming challenges in WAVE bioreactors without feedback controls for pH and dissolved oxygen

Yuk¹,

Baskar²,

Duffy

et al. 2011

Biotechnology Progress

View full text Add to dashboard Cite

The biopharmaceutical industry is increasing its use of the WAVE Bioreactor for culturing cells. Although this disposable bioreactor can be equipped to provide real-time pH and dissolved oxygen (DO) monitoring and control, our goal was to develop a process for culturing CHO cells in this system without relying on pH and DO feedback controls. After identifying challenges in culturing cells without controlling for pH and DO in the WAVE Bioreactor, we characterized O(2) and CO(2) transfer in the system. From these cell-free studies, we identified rock rate and rock angle as key parameters affecting O(2) transfer. We also identified the concentration of CO(2) in the incoming gas and the rate of gas flow into the headspace as key parameters affecting CO(2) transfer--and therefore pH--in the disposable culture chamber. Using a full-factorial design to evaluate the rock rate, rock angle, and gas flow rate defined for this WAVE Bioreactor process, we found comparable cell growth and pH profiles in the ranges tested for these three parameters in two CHO cell lines. This process supported cell growth, and maintained pH and DO within our desired range--pH 6.8-7.2 and DO exceeding 20% of air saturation--for six CHO cell lines, and it also demonstrated comparable cell growth and viability with the stirred-tank bioreactor process with online pH and DO control. By eliminating the use of pH and DO probes, this process provides a simple and more cost-effective method for culturing cells in the WAVE Bioreactor.

show abstract

“…Another example of intramolecular catalysis in the hydrolysis of phosphate diesters is the nucleophilic catalysis by the carboxylate group in the o-position relative to the ester linkage in aryl 2-carboxyphenyl phosphates 63 . The alkaline hydrolysis of the anions of these esters is 10 7 -10 8 faster than that of the analogous compounds without a CO 2 " group in the o-position.…”

Section: Hydrolysis Of Phosphate Diestersmentioning

confidence: 99%

“…The intramolecular catalysis of the hydrolysis of phosphate triesters has been investigated in a number of studies 95 ' 102 " 106 . In the hydrolysis of aryl 2-carboxyphenyl phosphates intramolecular nucleophilic catalysis by the ionised carboxy-group led to the preferential cleavage of the P-OAr bond 63 , which was explained by the inhibition of pseudorotation in the five-coordinated intermediate compounds containing two negatively charged oxygen atoms in the equatorial positions of the bipyramidal structure. In triesters of similar structure [but without a carboxylate group], there is only one negatively charged ligand in the equatorial position and pseudorotation is not hindered.…”

Section: Hydrolysis Of Phosphate Triestersmentioning

confidence: 99%

Kinetics of the Hydrolysis of Phosphate Esters

Bel’skii¹

1977

Russ. Chem. Rev.

View full text Add to dashboard Cite

The available information about the kinetics of the hydrolysis of phosphate esters in neutral, alkaline, and acidic media is considered and the mechanisms of the hydrolysis of various reactive forms of mono-, di-, and tri-esters are discussed. A systematic account is given of the rate constants, taking into account the type of ester and its reactive form. The bibliography includes 106 references. CONTENTS

show abstract

Intramolecular catalysis of phosphate diester hydrolysis. Nucleophilic catalysis by the neighbouring carboxy-group of the hydrolysis of aryl 2-carboxyphenyl phosphates

Cited by 31 publications

References 0 publications

Why did Nature select phosphate for its dominant roles in biology?

Why did Nature select phosphate for its dominant roles in biology?

Overcoming challenges in WAVE bioreactors without feedback controls for pH and dissolved oxygen

Kinetics of the Hydrolysis of Phosphate Esters

Contact Info

Product

Resources

About