Fractionation of DF32P-binding proteins of rat-liver cell fractions by deae-cellulose chromatography

Ramachandran, B. V.; Engström, Ellinor; Ågren, Gunnar

doi:10.1016/0006-2952(63)90181-3

Cited by 13 publications

(1 citation statement)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(14) and procaine (2) Ramachandran et al using solubilized microsomes and other solubilized cell fractions from rat liver, found four esterase peaks and corresponding radioactive peaks after fractionation by DEAE-cellulose chromatography and incubation with DF32P. They concluded that most esterase peaks took up radioactivity and that there were no radio active peaks without esterase activity (28,33). It was found that the esterase activity of each peak was not proportional to its radioactivity.…”

Section: Discussionmentioning

confidence: 99%

Studies on the Classification of the Enzymes Hydro-Lyzing Ester-Form Drugs in Liver Microsomes

Iwatsubo

1965

Japanese Journal of Pharmacology

View full text Add to dashboard Cite

The drug-metabolizing enzymes catalyzing such reactions as oxidation, reduction, conjugation and hydrolysis have been reported to be localized mainly in liver micro somes (1, 2). Microsomes may also be considered as hydrolytic particles (3). The en zymes hydrolyzing ester-form drugs, e.g. aspirin (4-6), procaine (7), cocaine (8-11), atropine (8,12, 13) and choline-esters (14, 15) have also been shown to be in the liver and some other tissues, but little is known 'about the properties and intracellular localization of these esterases as compared with cholinesterase which is closely related to synaptic trans mission. It appears of interest to investigate drug-metabolizing enzymes in liver micro somes further to elucidate their pharmacological actions and mechanisms of detoxication.As a fundamental classification of esterases, Aldridge (16) showed that 10-5 M organo phosphorous compounds inhibit many enzymes possessing carboxylic esterase activity while other esterases are unaffected. He has named the latter A-type and the former B-type esterase. Neither A nor B-type are sensitive to 10-5 M eserine. Cholinesterase is inhibited completely both by 10-6 M organophosphates and by 10-5 M eserine. Sub sequently A and B-types and cholinesterase in many vertebrate plasmata were separated electrophoretically by Goutier (17) and Augustinsson (18). Microsomal esterases have not been examined with this technique. The present paper describes experiments on the classification of esterases, especially drug-hydrolyzing enzymes, in liver microsomes of some rodents. The microsomes "solu bilized" with sodium deoxycholate were fractionated chromatographically or electro phoretically, and the sensitivities of the esterases in each fraction to inhibitors and their kinetics were investigated. METHODS Substrates and inhibitorsThe substrates used in this study were phenyl acetate (PhAc), phenyl butyrate (PhBu), tributyrin (TrBu), acetylcholine chloride (AcCh), butyrylcholine iodide (BuCh), polyoxyethylene sorbitan monolaurate (Tween 20), aspirin and hydrochlorides of cocaine, procaine, hexylcaine and tetracaine, which were obtained commercially. The esterase inhibitors used as selective inhibitors were eserine sulfate and diiso propyl fluorophosphate (DFP, in propylene glycol).

show abstract

Section: Discussionmentioning

confidence: 99%