Metal-Catalyzed Photooxidation of Histidine in Human Growth Hormone

Chang, Suh H.; Teshima, Glen; Milby, Terry; Gillece-Castro, Beth; Canova-Davis, Eleanor

doi:10.1006/abio.1996.9899

Cited by 47 publications

(32 citation statements)

References 4 publications

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“…HPLC-MS 2 analysis confirmed that these new peaks were appropriately assigned to modification of the His residue. The structures of His+14 and His+32 have been previously characterized as the 2-imidazolone and as the hydrated imidazolone species, respectively [11,48]. Since 1 O 2 reacts with the unprotonated imidazole, the rate constant of His increases at higher pH consistent with our observation that the relative intensity of the M+14 and M+32 peaks increased when subjected to irradiation at higher pH (data not shown).…”

Section: Modification Of Peptides By 1 Osupporting

confidence: 86%

“…His is known to be the most reactive of the proteogenic amino acids with 1 O 2 , with several observed products as shown in Figure 1A [11,48]. The initial product appears to be the cyclic endoperoxide shown in Figure 1A which can be trapped at -100 °C but decomposes to the hydroperoxide at-78 °C and subsequently to the 2-imidazolone which can be hydrated at any of the carbon positions [16].…”

Section: Modification Of Peptides By 1 Omentioning

confidence: 99%

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Oxidative modification of cytochrome c by singlet oxygen

Kim¹,

Rodriguez²,

Guo³

et al. 2008

Free Radical Biology and Medicine

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Singlet oxygen ( 1 O 2 ) is a reactive oxygen species that may be generated in biological systems. Photodynamic therapy generates 1 O 2 by photoexcitation of sensitizers resulting in intracellular oxidative stress and induction of apoptosis. 1 O 2 oxidizes amino acid side chains of proteins and inactivates enzymes when generated in vitro. Among proteogenic amino acids, His, Tyr, Met, Cys, and Trp are known to be oxidized by 1 O 2 at physiological pH. However, there is a lack of direct evidence of oxidation of proteins by 1 O 2 . Because 1 O 2 is difficult to detect in cells, identifying oxidized cellular products uniquely derived from 1 O 2 could serve as a marker of its presence. In the present study, 1 O 2 reactions with model peptides analyzed by tandem mass spectrometry provide insight into the mass of prominent adducts formed with the reactive amino acids. Analysis by MALDI-TOF and tandem mass spectrometry of peptides of cytochrome c exposed to 1 O 2 generated by photoexcitation of the phthalocyanine Pc 4 showed unique oxidation products, which might be used as markers of the presence of 1 O 2 in the mitochondrial intermembrane space. Differences in the elemental composition of the oxidized amino acid residues observed with cytochrome c and the model peptides suggest the protein environment can affect the oxidation pathway.

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Section: Modification Of Peptides By 1 Osupporting

confidence: 86%

Section: Modification Of Peptides By 1 Omentioning

confidence: 99%

Oxidative modification of cytochrome c by singlet oxygen

Kim¹,

Rodriguez²,

Guo³

et al. 2008

Free Radical Biology and Medicine

View full text Add to dashboard Cite

show abstract

“…In general, photoinstability presents a problem for various pharmaceutical proteins, such as human growth hormone44 and monoclonal immunoglobulin G,45 yet few mechanistic studies have addressed this problem. The obvious remedy of photoinstability would be the exclusion of light.…”

Section: Discussionmentioning

confidence: 99%

Solid-State Photodegradation of Bovine Somatotropin (Bovine Growth Hormone): Evidence for Tryptophan-Mediated Photooxidation of Disulfide Bonds

Miller

Hageman²,

Thamann³

et al. 2003

Journal of Pharmaceutical Sciences

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“…Hara 23 studied the oxidation of monomeric and protein histidine, by photosynthesizers or metal catalysis and found aspartic acid and urea to be the final products. Others have shown that histidine in proteins and peptides can specifically be oxidized by irradiation with visible light in the presence of a suitable photo sensitizer 24 or in the presence of a suitable metal such as zinc, copper or iron 25,26 to produce the 2-oxo-imidazole derivative without breaking the peptide bond between the amino acids of the peptide. Tomita et al 27 studied the photoxidation of Nbenzoylhistidine and isolated a handful of products, among them N-benzoyl-aspartate and 6a-hydroxy-2-oxo-4-(phenylcarbonyl) octahydropyrrolo-[3,2-d]imidazole-5-carboxylic acid similar to that of 8.…”

Section: Resultsmentioning

confidence: 99%