Showing papers on "Acetylthiocholine published in 1983"
TL;DR: A highly sensitive microfluorometric assay for cholinesterases has been developed, providing a linear determination of the thiocholine produced over a period of at least 30 h at room temperature, and may be used for monitoring the kinetics of enzymatic activities in microscale reaction mixtures.
74 citations
TL;DR: Four enzymes can be classified as intermediate type cholinesterases according to their substrate specificity and to their inhibition constants and the possible role of different brain cholineterases for the development of atypical symptoms following organophosphate intoxication is discussed.
11 citations
TL;DR: The results suggest that I is a mixture of carboxylesterases and cholinesterases, that II is an arylesterase, and that III contains car boxylesterase and JH esterase enzymes.
Abstract: 1.
1. Three esterolytic fractions (I–III) were partially purified by chromatographic procedures from pharate pupal moulting fluid of the tobacco hornworm, Manduca sexta L.
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2. Maximum activity toward 1-naphthyl acetate occurred at pH ≥ 8 for I and between pH 6 and 7 for II and III.
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3. The apparent Michaelis constants for 1-naphthyl acetate were 145, ≥500 and 46 μM for I, II and III, respectively.
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4. I and III were inhibited by diisopropylphosphorofluoridate. II was inactivated by p-chloromercuribenzoate.
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5. I also hydrolyzed acetylthiocholine and this activity was inhibited by eserine.
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6. While all of the fractions hydrolyzed juvenile hormone, III was greater than 10 times more active than the other enzymes.
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7. These results suggest that I is a mixture of carboxylesterases and cholinesterases, that II is an arylesterase, and that III contains carboxylesterase and JH esterase enzymes.
2 citations