The decomposition of dl-methionine sulfoxide in 6 N hydrochloric acid

Floyd, Norman F.; Cammaroti, Mary S.; Lavine, Theodore F.

doi:10.1016/0003-9861(63)90239-x

Cited by 25 publications

(10 citation statements)

References 7 publications

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“…Acid hydrolysis was carried out with the addition of 0.01 % 2-mercaptoethanol to prevent methionine decomposition [25]. However, 2-mercaptoethanol is capable of reducing methionine sulphoxide to methionine [26]. Methionine sulphoxide and methionine sulphone can also undergo other transformations on acid hydrolysis [26].…”

Section: Effect Of the H202 On The Amino Acid Composition Of Xc-galacmentioning

confidence: 99%

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Role of methionine in the active site of α-galactosidase from Trichoderma reesei

Kachurin

Golubev

Geisow³

et al. 1995

Biochemical Journal

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alpha-Galactosidase from Trichoderma reesei when treated with H2O2 shows a 12-fold increase in activity towards p-nitrophenyl alpha-D-galactopyranoside. A similar effect is produced by the treatment of alpha-galactosidase with other non-specific oxidants: NaIO4, KMnO4 and K4S4O8. In addition to the increase in activity, the Michaelis constant rises from 0.2 to 1.4 mM, the temperature coefficient decreases by a factor of 1.5 and the pH-activity curve falls off sharply with increasing pH. Galactose (a competitive inhibitor of alpha-galactosidase; Ki 0.09 mM for the native enzyme at pH 4.4) effectively inhibits oxidative activation of the enzyme, because the observed activity changes are related to oxidation of the catalytically important methionine in the active site. NMR measurements and amino acid analysis show that oxidation to methionine sulphoxide of one of five methionines is sufficient to activate alpha-galactosidase. Binding of galactose prevents this. Oxidative activation does not lead to conversion of other H2O2-sensitive amino acid residues, such as histidine, tyrosine, tryptophan and cysteine. The catalytically important cysteine thiol group is quantitatively titrated after protein oxidative activation. Further oxidation of methionines (up to four of five residues) can be achieved by increasing the oxidation time and/or by prior denaturation of the protein. Obviously, a methionine located in the active site of alpha-galactosidase is more accessible. The oxidative-activation phenomenon can be explained by a conformational change in the active site as a result of conversion of non-polar methionine into polar methionine sulphoxide.

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Section: Effect Of the H202 On The Amino Acid Composition Of Xc-galacmentioning

confidence: 99%

“…However, 2-mercaptoethanol is capable of reducing methionine sulphoxide to methionine [26]. Methionine sulphoxide and methionine sulphone can also undergo other transformations on acid hydrolysis [26]. For these reasons we used alkaline hydrolysis.…”

Section: Effect Of the H202 On The Amino Acid Composition Of Xc-galacmentioning

confidence: 99%

Role of methionine in the active site of α-galactosidase from Trichoderma reesei

Kachurin

Golubev

Geisow³

et al. 1995

Biochemical Journal

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“…Even if the sulphoxide is not racemic in the protein, it is naturally racemized very rapidly under the conditions of baryta-catalysed hydrolysis, and two peaks of equal area appear on the analyser trace. The absence of sulphoxide in acid-catalysed hydrolysates of oxidized proteins has been explained by and by Floyd, Cammaroti & Lavine (1963), who found that methionine sulphoxide reverts to the parent compound under the conditions of acid hydrolysis.…”

Section: Resultsmentioning

confidence: 99%

The ROLE OF METHIONINE IN Α-Chymotrypsin-Catalysed REACTIONS

Knowles¹

1965

Biochemical Journal

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1. The reaction of alpha-chymotrypsin with sodium periodate at pH5.0 has been investigated. The enzyme consumes 2 moles of periodate/mole, and there is a concomitant fall in enzymic activity (with respect to l-tyrosine ethyl ester) to 55% of that of the native enzyme. After 3hr. no further change is observed in periodate uptake or in catalytic activity. 2. The oxidized enzyme is a homogeneous preparation of partially active chymotrypsin. 3. In the oxidized enzyme, one of the two methionine residues in the molecule has been converted into its sulphoxide. It is this reaction only that is responsible for the loss of activity. 4. The rate constants for the enzyme-catalysed acylation and deacylation reactions are unaltered by oxidation of the enzyme, both for a non-specific substrate (p-nitrophenyl acetate), and for three specific substrates: N-acetyl-l-tryptophan ethyl ester, N-acetyl-l-tryptophanamide and N-acetyl-l-valine ethyl ester. 5. The K(m) values for the aromatic substrates with the oxidized enzyme are twice those with the native enzyme. No change in Michaelis constant is seen for the non-aromatic substrate N-acetyl-l-valine ethyl ester. 6. The evidence points to the oxidized methionine residue in the modified enzyme being situated in the locus of the active site at which aromatic (or bulky) side chains of the substrates are bound.

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“…2A, Table 1) [3,. During HC1 hydrolysis of proteins, most of the methionine S-oxide is reduced into methionine, but a small portion of it decomposes into homocysteine and formaldehyde [22,23]. On amino acid analysis of the HCl hydrolysate of the resilium protein, a small amount (1 -2 mo1/100 mol total amino acids) of homocysteic acid, an oxidation product of homocysteine, was detected at a retention time very close to that of cysteic acid.…”

Section: Discussionmentioning

confidence: 99%

Desmosine and isodesmosine as cross‐links in the hinge‐ligament protein of bivalves

Kikuchi

Tsuchikura

Hirama

et al. 1987

European Journal of Biochemistry

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1. Desmosine and isodesmosine were detected in an invertebrate molluscan species, i.e. in an insoluble protein in the hinge ligament of a bivalve species, Sakhalin surf clam (Pseudocardium sachalinensis, in family Mactridae). The protein is rich in glycine and methionine S‐oxide but devoid of hydroxyproline and hydroxylysine. 2. 3,3′‐Methylenebistyrosine was also detected in the HCl hydrolysate of the hinge‐ligament protein, but it was found to be an artefact produced from tyrosine and formaldehyde derived from methionine S‐oxide during the HCl hydrolysis of the protein.

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The decomposition of dl-methionine sulfoxide in 6 N hydrochloric acid

Cited by 25 publications

References 7 publications

Role of methionine in the active site of α-galactosidase from Trichoderma reesei

Role of methionine in the active site of α-galactosidase from Trichoderma reesei

The ROLE OF METHIONINE IN Α-Chymotrypsin-Catalysed REACTIONS

Desmosine and isodesmosine as cross‐links in the hinge‐ligament protein of bivalves

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