Alkylation and Oxidation of Methionine in Bovine Parathyroid Hormone: Effects on Hormonal Activity and Antigenicity<sup>*</sup>

Tashjian, Armen H.; Ontjes, David A.; Munson, Paul L.

doi:10.1021/bi00896a029

Cited by 95 publications

(33 citation statements)

References 26 publications

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“…bility for each of these residues to be located within the hy- (19). We have also shown that such oxidized PTH does not bind to kidney receptors (20).…”

mentioning

confidence: 92%

A theoretical study of the structure of parathyroid hormone.

Zull¹,

Lev²

1980

Proc. Natl. Acad. Sci. U.S.A.

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Theoretical analysis of the tertiary and secondary structure of parathyroid hormone was conducted. By combining interpretations from this analysis with chemical data available in the literature, certain structural features of the hormone are consistently predicted. The proposed model for the hormone contains two domains dominated by hydrophobic clustering of critical residues within each domain and separated by an exposed linker region. In the prediction of two domains with a linker region, the model is similar to that proposed by Fiskin et al. [Fiskin, A.M., Cohn, D.M. & Peterson, G.S. (1977) J. Biol. Chem. 252, 8261-8268], but it differs significantly in other respects. The proposed structural features are apparent in the bovine, human, and porcine species of hormone.

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“…bility for each of these residues to be located within the hy- (19). We have also shown that such oxidized PTH does not bind to kidney receptors (20).…”

mentioning

confidence: 92%

A theoretical study of the structure of parathyroid hormone.

Zull¹,

Lev²

1980

Proc. Natl. Acad. Sci. U.S.A.

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“…The calcium-mobilizing and phosphaturic activities of parathyroid hormone are lost during oxidation of the polypeptide by hydrogen peroxide (15,23,24). The activities that are lost during oxidation can be recovered by treatment of the oxidized hormone with reducing agents such as cysteine or 2-mercaptoethanol (15,23).…”

Section: Discussionmentioning

confidence: 99%

“…Thyrocalcitonin was incubated with 0.2M hydrogen peroxide in 0.1M Tris, pH 7.5, or in dilute HC1 (0.01-O.OOIN), at 37 C for 1.5 hr. Oxidation was terminated by the addition of 0.25 mg of catalase (Nutritional Biochemical Corporation) per ml of reaction mixture (15). Attempts were also made to oxidize thyrocalcitonin by bubbling a mixture of 95 % oxygen-5 % carbon dioxide through a solution of the hormone in 0.1M Tris, pH 7.5, at 37 C for 1.5 hr.…”

Section: Methodsmentioning

confidence: 99%

Stability of the Hypocalcemic Activity of Porcine Thyrocalcitonin

Tashjian

Warnock

1967

Endocrinology

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Porcine thyrocalcitonin was modified by enzymatic and chemical treatment for the purpose of studying the interrelationships between structure and hypocalcemic activity. Enzymatic treatment with trypsin, chymotrypsin, pepsin and polyphenyl oxidase led to rapid and complete inactivation of the hypocalcemic activity. We conclude from these experiments that thyrocalcitonin either is a simple polypeptide or contains a peptide moiety which is absolutely essential for hypocalcemic activity. Incubation of thyrocalcitonin in dilute HC1 or neutral Tris buffer at elevated temperature was accompanied by gradual loss of activity. Inactivation was also seen after treatment with hydrogen peroxide, photooxidation and treatment with n-bromosuccinimide, results demonstrating that there is at least one site in the thyrocalcitonin molecule that is sensitive to oxidation. The hypocalcemic activity which was lost during incubation with hydrogen peroxide could not be recovered by treatment of the oxidized products with cysteine, 2-mercaptoethanol or dithiothreitol. There were no detectable changes in hypocalcemic activity either after enzymatic treatment with carboxypeptidase A, leucine aminopeptidase and neuraminidase, or after chemical treatment with 2-OH-5-nitrobenzyl bromide, N-acetylimidazole, p-OHmercuribenzoate, iodoacetate and cyanogen bromide. Because thyrocalcitonin has not yet been purified, the sites of the modifications produced by various treatments cannot be shown. Results of experiments in which no loss of hypocalcemic activity was detected must be viewed with caution since it was not possible to show that amino acid residues in thyrocalcitonin were modified. However, these data may help to explain losses of hypocalcemic activity which occur during handling and to suggest new approaches to purification and characterization of thyrocalcitonin. (Endocrinology 81: 306, 1967)

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“…This has also been observed experimentally (72). Despite the popularity of these reagents, it is evident from the literature that they can react with other amino acids, mainly methionine but also histidine and lysine (3,(72)(73)(74)(75)(76)(77)(78). These side reactions have also been observed in peptide-mapping applications (6).…”

Section: Alkylation With Iodoacetic Acid (Iaa) and Iodoacetamide (Iam)mentioning

confidence: 78%

Sample Preparation for Peptide Mapping— A Pharmaceutical Quality-Control Perspective

Lundell

Schreitmüller

1999

Analytical Biochemistry

131

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Alkylation and Oxidation of Methionine in Bovine Parathyroid Hormone: Effects on Hormonal Activity and Antigenicity^*

Cited by 95 publications

References 26 publications

A theoretical study of the structure of parathyroid hormone.

A theoretical study of the structure of parathyroid hormone.

Stability of the Hypocalcemic Activity of Porcine Thyrocalcitonin

Sample Preparation for Peptide Mapping— A Pharmaceutical Quality-Control Perspective

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Alkylation and Oxidation of Methionine in Bovine Parathyroid Hormone: Effects on Hormonal Activity and Antigenicity*

Cited by 95 publications

References 26 publications

A theoretical study of the structure of parathyroid hormone.

A theoretical study of the structure of parathyroid hormone.

Stability of the Hypocalcemic Activity of Porcine Thyrocalcitonin

Sample Preparation for Peptide Mapping— A Pharmaceutical Quality-Control Perspective

Contact Info

Product

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Alkylation and Oxidation of Methionine in Bovine Parathyroid Hormone: Effects on Hormonal Activity and Antigenicity^*