Enzyme-Like Activities Associated With Albumin

Taylor, Ronald P.

doi:10.1016/b978-0-08-019603-9.50015-6

Cited by 10 publications

(4 citation statements)

References 67 publications

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“…In many of the studies on the enzymatic activities associated with albumin it was not clear if the activities were associated with the albumin molecule itself, or with minor proteins that cofractionated with albumin (Taylor, 1977). Ortigoza-Ferado et al (1984) resolved human serum paraoxonase by gel filtration chromatography into two fractions: 1.…”

Section: Lack Of the Edta Stable Paraoxonase In An Individual With Anmentioning

confidence: 98%

The human serum paraoxonase—Polymorphism and specificity

Mallinckrodt¹,

Diepgen

1988

Toxicological & Environmental Chemistry

111

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Human serum contains EDTA-sensitive (Ca ++ -dependent) and EDTA-stable (albumin) paraoxonases which hydrolyse paraoxon, 0,0-diethyl,0-4-nitrophenyl phosphate.In Caucasians the EDTA-sensitive enzyme shows a genetically determined polymorphism which is governed by two alleles. In typical Mongoloid or Negro populations this polymorphism is expressed to a lesser degree, and in a few samples (e.g. Aborigines) it cannot be observed at all. The distribution of the activity of the EDTAstable (albumin) paraoxonase is unimodal.Many authors supposed that paraoxonase is an arylesterase (EC 3.1.1.2) which means that it is also able to hydrolyse phenylacetate or β-naphthylacetate. New investigations have shown that the human serum fractions splitting paraoxon can be separated from those hydrolysing phenylacetate and related substrates.The polymorphism of the EDTA-sensitive human serum paraoxonase can be applied to investigations concerning specificity. From this it becomes evident that this enzyme is rather specific. Already slight changes of the paraoxon molecule lead to a decrease of activity. On the other hand the enzyme seems to hydrolyse also phosphonic acid esters and 4-nitrophenylacetate in the same way like paraoxon (polymorphism).There is a linkage relationship of paraoxonase with cystic fibrosis and DNA markers. According to these results the (EDTA-sensitive) paraoxonase locus is on the human chromosome 7.A high serum paraoxonase level actually protects serum cholinesterase (EC 3.1.1.8) and has to be considered in biological monitoring of workers exposed to parathion.

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Section: Lack Of the Edta Stable Paraoxonase In An Individual With Anmentioning

confidence: 98%

The human serum paraoxonase—Polymorphism and specificity

Mallinckrodt¹,

Diepgen

1988

Toxicological & Environmental Chemistry

111

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“…HSA has been found to possess esterase-like properties [24][25][26][61][62][63]. Best characterized is probably the catalysis of p-nitrophenyl acetate decomposition [26,63,64] which will discussed further below.…”

Section: Hydrolysis In Hsa Solutionmentioning

confidence: 99%

“…Further, sustained release of 5-fluorouracil prodrugs with affinity for HSA was found to be effective against sarcoma in a mouse model [21][22][23]. In addition to the well-known ligand binding characteristics, HSA has been associated with esterase-like properties [9,[24][25][26] which may be of potential interest in the prodrug setting in relation to regeneration of parent compound.…”

Section: Introductionmentioning

confidence: 99%

Bioreversible Derivatives of Phenol. 1. The Role of Human Serum Albumin as Related to the Stability and Binding Properties of Carbonate Esters with Fatty Acid-like Structures in Aqueous Solution and Biological Media

Østergaard

Larsen

2007

Molecules

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Abstract:With the overall objective of assessing the potential of utilizing plasma protein binding interactions in combination with the prodrug approach for improving the pharmacokinetics of drug substances, a series of model carbonate ester prodrugs of phenol, encompassing derivatives with fatty acid-like structures, were characterized in vitro. Stability of the derivatives was studied in aqueous solution, human serum albumin solution, human plasma, and rat liver homogenate at 37 o C. Stability of the derivatives in aqueous solution varied widely, with half-lives ranging from 31 to 1.7 × 10 4 min at pH 7.4and 37 o C. The carbonate esters were subject to catalysis by plasma esterases except for the t-butyl and acetic acid derivatives, which were stabilized in both human plasma and human serum albumin solutions relative to buffer. In most cases, however, hydrolysis was accelerated in the presence of human serum albumin indicating that the derivatives interacted with the protein, a finding which was confirmed using the p-nitrophenyl acetate kinetic assay. Different human serum albumin binding properties of the phenol model prodrugs with fatty acid-like structure and neutral carbonate esters were observed. In the context of utilizing plasma protein binding in combination with the prodrug approach for optimizing drug pharmacokinetics, the esterase-like properties of human serum albumin towards the carbonate esters potentially allowing the protein to act as a catalyst of parent compound regenerations is interesting.

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“…Incubations containing albumin saturated with fatty acids reduced the occurrence of the acrosome reaction for a given interval as compared to incubations containing fatty acid-free albumin (Lui and Meizel 1977). It has been recognized that serum albumin is contaminated by hormones (McMenamy 1977) and enzymes (Taylor 1977), and that these ligands may influence capacitation (Meizel 1978). Singleton and Killian (1983) have suggested the phospholipase activity in bovine serum albumin (BSA) is a contributing factor to the beneficial effects of BSA on capacitation.…”

Section: Effect Of P-bromophenacyl Bromide (P-bpb)mentioning

confidence: 99%