SH groups in the α-naphthyl acetate esterase in the thyroid of the guinea-pig: A histochemical study
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SH groups in the α-naphthyl acetate esterase in the thyroid of the guinea-pig : A histochemical study. / Kirkeby, S.
In: Histochemistry, Vol. 49, No. 2, 1976, p. 145-55.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - SH groups in the α-naphthyl acetate esterase in the thyroid of the guinea-pig
T2 - A histochemical study
AU - Kirkeby, S.
N1 - Keywords: Animals; Carboxylic Ester Hydrolases; Guinea Pigs; Histocytochemistry; Naphthol AS D Esterase; Sulfhydryl Compounds; Sulfhydryl Reagents; Thyroid Gland
PY - 1976
Y1 - 1976
N2 - The alpha-naphthyl acetate esterase in both group I and group II thyroid cells is shown to contain SH groups since there is a decline in activity in both cell groups when certain sulfhydryl reagents [DTNB; 5,5'-Dithiobis-(2-nitrobenzoic acid)-AgNO3-Mersalyl-PCMB (parachloro mercuribenzoate) + urea] are added to the incubation media. Thus the inhibition is by far the greatest in group I cells, which also show the greatest activity after incubation in conventional media, when long fixation and storage times are used. In all cases the inhibiting effect was complete or almost completely reversed if cysteine was added to the incubation media in equivalent concentrations to the SH blocker. There were great differences among the sulfhydryl reagents used in their ability to bring about enzyme inhibition. The alkylating agents NEM (N-ethylmaleimide) and iodoacetamide had no or little effect while PCMB could only inhibit the activity of the alpha-naphthylacetate esterase if the enzyme was denaturated with 5 M urea. The maximal inhibitory effect of PCMB was only obtained when NaCl was added to the incubation media. The most effective inhibitor was AgNO3.
AB - The alpha-naphthyl acetate esterase in both group I and group II thyroid cells is shown to contain SH groups since there is a decline in activity in both cell groups when certain sulfhydryl reagents [DTNB; 5,5'-Dithiobis-(2-nitrobenzoic acid)-AgNO3-Mersalyl-PCMB (parachloro mercuribenzoate) + urea] are added to the incubation media. Thus the inhibition is by far the greatest in group I cells, which also show the greatest activity after incubation in conventional media, when long fixation and storage times are used. In all cases the inhibiting effect was complete or almost completely reversed if cysteine was added to the incubation media in equivalent concentrations to the SH blocker. There were great differences among the sulfhydryl reagents used in their ability to bring about enzyme inhibition. The alkylating agents NEM (N-ethylmaleimide) and iodoacetamide had no or little effect while PCMB could only inhibit the activity of the alpha-naphthylacetate esterase if the enzyme was denaturated with 5 M urea. The maximal inhibitory effect of PCMB was only obtained when NaCl was added to the incubation media. The most effective inhibitor was AgNO3.
U2 - 10.1007/BF00495678
DO - 10.1007/BF00495678
M3 - Journal article
C2 - 993065
VL - 49
SP - 145
EP - 155
JO - Histochemistry
JF - Histochemistry
SN - 0301-5564
IS - 2
ER -
ID: 10026856