The rates of enzymic hydrolysis of phosphoric esters

King, E. J.; Delory, G. E.

doi:10.1042/bj0331185

Cited by 75 publications

(14 citation statements)

References 9 publications

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“…Sodium malonate (Eastman Organic Chemicals, Rochester, New York) was used to buffer over the range pH 2.6 to 6.6. However, the substrate disodium phenyl phosphate is itself a powerful buffer (32) and contributes significantly to the buffer capacity of the system. The actual pH of the reaction mixture was determined after mixing the reagents in the same pro-portions employed in the automated assay system and incubation at 37°C.…”

Section: Materials and Mettiodsmentioning

confidence: 99%

Studies on Isolated Cell Components

Schuel

Anderson

1964

The Journal of Cell Biology

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The zonal ultracentrifuge has been used to separate the major components of rat liver brei (soluble phase, ribosomes, microsomes, mitochondria, membranous fragments, and nuclei) during one ccntrifugation, by using a 1200 ml sucrose gradient varying linearly with radius from 17 to 55 per cent (w/w) with a "cushion" of 66 per cent sucrose at the rotor edge at speeds up to 30,000 RVM. Liver brei was found to contain a family of phosphatascs (phenol disodium phosphate substrate, sodium malonate buffers and Turgitol NPX, a non-ionic detergent). Activity maxima at pH 4.1 and 5.9 were observed in untreated brei prepared in 0.25 i sucrose. "l~he addition of the non-ionic detergent Turgitol NPX selectively caused the release of considerable additional activity between these optima. The activity measured at pH 4. l was primarily associated with the cytoplasmic granules, while the activities at pH 4.8, 5.4 and 5.9 were found in both soluble phase and particulate-mitochondria and membranous fractions. The activities present beyond the region of the gradient occupied by the soluble phase (sample layer) were all bound to particles sedimentable at 105,536 g (average) in the preparative ultracentrifuge. The data suggest that the different activities are not similarly distributed between soluble phase and particulate fractions. When the data are expressed in terms of specific activity, the area in the gradient between the microsomes and mitochondria now appears richest in all the acid phenyl phosphatase activities measured, while the soluble phase and larger particulate fractions appear relatively poor in activity. This part of the gradient is occupied by small, dense granules which may be the so called lysosomcs. Pretreatment of the brei with Turgitol NPX prior to fractionation in the zonal ultracentrifuge resulted in the solubilization of acid phenyl phosphatase activities (almost all the activity was in the sample zone of the gradient) and the non-specific destruction of the formed elements of the brei. Essentially all of the activities present in the original brei measured under these conditions were recovered after zonal ultracentrifuge fractionations.

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Section: Materials and Mettiodsmentioning

confidence: 99%

Studies on Isolated Cell Components

Schuel

Anderson

1964

The Journal of Cell Biology

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“…Elle rejoint l'une des hypothbses faites pour expliquer le mecanisme de l'activation par le magnesium, laquelle apparait comme de m&me nature que celle due aux autres cations divalents. En outre il a 6th observe que la phosphatase intestinale presente A pH 9.2 une augmentation de son affinite pour le substrat quand on enrichit en magnesium son milieu d'action (112a) et qu'elle s'unit aux esters A 1'6tat de mol6cule non dissoci6e (66). Elle a par ailleurs 6th rattachbe A la formation d'un complexe actif: enzyme-magnesium (63) et l'une des opinions Bmises pour expliquer le r81e de celui-ci dans la catalyse phosphatasique est la suivante.…”

Section: H Dissociation Et Reconstitution De La Phosphatase Alcalineunclassified

Phosphatase Alcaline

Roche

Thoại

1950

Advances in Enzymology - And Related Areas of Molecular Biology

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“…To shorten the procedure, Bessey et al (1946) employed a new substrate, p-nitrophenyl phosphate. Its preparation is described by King and Nicholson (1939) and has been characterised by King and Delory (1939). This allowed for instantaneous colour development at high pH.…”

Section: Introductionmentioning

confidence: 99%