Evidence implicating a novel thiol methyltransferase in the detoxification of glucosinolate hydrolysis products in Brassica oleracea L.

J. Attieh, K. F. Kleppinger-Sparace, C. Nunes, S. A. Sparace, Hargurdeep S. Saini

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

The physiological relevance of a novel thiol methyltransferase from cabbage, and its possible role in sulphur metabolism have been investigated. The enzyme was absent from the chloroplast, the site of sulphate reduction, and was localized in the cytosol. Potential substrates were initially screened on the basis of their ability to inhibit the methylation of iodide, a previously known substrate for the enzyme. Thiocyanate, 4,4'-thiobisbenzenethiol, thiophenol, and thiosalicylic acid were identified as possible substrates. Methylation of these thiols by the purified enzyme using [Methyl-3H]S-adenosyl-L-methionine confirmed their nature as substrates. The purified enzyme strongly preferred thiocyanate as a methyl acceptor. The enzyme had K(m) values of 11, 51, 250 and 746 mmol m-3 for thiocyanate, 4,4'-thiobisbenzenethiol, thiophenol and thiosalicylic acid, respectively. The identity of methylthiocyanate as the product of thiocyanate methylation by the purified enzyme was confirmed by mass spectrometry. The enzyme was strictly associated with glucosinolate-containing plants. Thiol substrates of the enzyme are known products of glucosinolate hydrolysis. Our observations indicate that this enzyme could be involved in the detoxification of reactive thiols produced upon glucosinolate degradation in these plants.

Original languageEnglish
Pages (from-to)165-174
Number of pages10
JournalPlant, Cell and Environment
Volume23
Issue number2
DOIs
Publication statusPublished - 1 Jan 2000
Externally publishedYes

Fingerprint

thiol S-methyltransferase
Glucosinolates
Brassica
glucosinolates
Brassica oleracea
Hydrolysis
hydrolysis
thiocyanates
Enzymes
enzymes
thiols
methylation
enzyme substrates
Sulfhydryl Compounds
Methylation
S-adenosylmethionine
acids
iodides
S-Adenosylmethionine
cabbage

Cite this

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title = "Evidence implicating a novel thiol methyltransferase in the detoxification of glucosinolate hydrolysis products in Brassica oleracea L.",
abstract = "The physiological relevance of a novel thiol methyltransferase from cabbage, and its possible role in sulphur metabolism have been investigated. The enzyme was absent from the chloroplast, the site of sulphate reduction, and was localized in the cytosol. Potential substrates were initially screened on the basis of their ability to inhibit the methylation of iodide, a previously known substrate for the enzyme. Thiocyanate, 4,4'-thiobisbenzenethiol, thiophenol, and thiosalicylic acid were identified as possible substrates. Methylation of these thiols by the purified enzyme using [Methyl-3H]S-adenosyl-L-methionine confirmed their nature as substrates. The purified enzyme strongly preferred thiocyanate as a methyl acceptor. The enzyme had K(m) values of 11, 51, 250 and 746 mmol m-3 for thiocyanate, 4,4'-thiobisbenzenethiol, thiophenol and thiosalicylic acid, respectively. The identity of methylthiocyanate as the product of thiocyanate methylation by the purified enzyme was confirmed by mass spectrometry. The enzyme was strictly associated with glucosinolate-containing plants. Thiol substrates of the enzyme are known products of glucosinolate hydrolysis. Our observations indicate that this enzyme could be involved in the detoxification of reactive thiols produced upon glucosinolate degradation in these plants.",
keywords = "Brassica oleracea, Brassicaceae, Detoxification, Glucosinolates, Halomethanes, Methanethiol, Sulfur, Thiocyanate, Thiol methyltransferase",
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Evidence implicating a novel thiol methyltransferase in the detoxification of glucosinolate hydrolysis products in Brassica oleracea L. / Attieh, J.; Kleppinger-Sparace, K. F.; Nunes, C.; Sparace, S. A.; Saini, Hargurdeep S.

In: Plant, Cell and Environment, Vol. 23, No. 2, 01.01.2000, p. 165-174.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Evidence implicating a novel thiol methyltransferase in the detoxification of glucosinolate hydrolysis products in Brassica oleracea L.

AU - Attieh, J.

AU - Kleppinger-Sparace, K. F.

AU - Nunes, C.

AU - Sparace, S. A.

AU - Saini, Hargurdeep S.

PY - 2000/1/1

Y1 - 2000/1/1

N2 - The physiological relevance of a novel thiol methyltransferase from cabbage, and its possible role in sulphur metabolism have been investigated. The enzyme was absent from the chloroplast, the site of sulphate reduction, and was localized in the cytosol. Potential substrates were initially screened on the basis of their ability to inhibit the methylation of iodide, a previously known substrate for the enzyme. Thiocyanate, 4,4'-thiobisbenzenethiol, thiophenol, and thiosalicylic acid were identified as possible substrates. Methylation of these thiols by the purified enzyme using [Methyl-3H]S-adenosyl-L-methionine confirmed their nature as substrates. The purified enzyme strongly preferred thiocyanate as a methyl acceptor. The enzyme had K(m) values of 11, 51, 250 and 746 mmol m-3 for thiocyanate, 4,4'-thiobisbenzenethiol, thiophenol and thiosalicylic acid, respectively. The identity of methylthiocyanate as the product of thiocyanate methylation by the purified enzyme was confirmed by mass spectrometry. The enzyme was strictly associated with glucosinolate-containing plants. Thiol substrates of the enzyme are known products of glucosinolate hydrolysis. Our observations indicate that this enzyme could be involved in the detoxification of reactive thiols produced upon glucosinolate degradation in these plants.

AB - The physiological relevance of a novel thiol methyltransferase from cabbage, and its possible role in sulphur metabolism have been investigated. The enzyme was absent from the chloroplast, the site of sulphate reduction, and was localized in the cytosol. Potential substrates were initially screened on the basis of their ability to inhibit the methylation of iodide, a previously known substrate for the enzyme. Thiocyanate, 4,4'-thiobisbenzenethiol, thiophenol, and thiosalicylic acid were identified as possible substrates. Methylation of these thiols by the purified enzyme using [Methyl-3H]S-adenosyl-L-methionine confirmed their nature as substrates. The purified enzyme strongly preferred thiocyanate as a methyl acceptor. The enzyme had K(m) values of 11, 51, 250 and 746 mmol m-3 for thiocyanate, 4,4'-thiobisbenzenethiol, thiophenol and thiosalicylic acid, respectively. The identity of methylthiocyanate as the product of thiocyanate methylation by the purified enzyme was confirmed by mass spectrometry. The enzyme was strictly associated with glucosinolate-containing plants. Thiol substrates of the enzyme are known products of glucosinolate hydrolysis. Our observations indicate that this enzyme could be involved in the detoxification of reactive thiols produced upon glucosinolate degradation in these plants.

KW - Brassica oleracea

KW - Brassicaceae

KW - Detoxification

KW - Glucosinolates

KW - Halomethanes

KW - Methanethiol

KW - Sulfur

KW - Thiocyanate

KW - Thiol methyltransferase

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DO - 10.1046/j.1365-3040.2000.00541.x

M3 - Article

VL - 23

SP - 165

EP - 174

JO - Plant, Cell and Environment

JF - Plant, Cell and Environment

SN - 0140-7791

IS - 2

ER -