Identification of a tyrosine residue in ovine placental lactogen as essential for its binding to receptors

Cymes, Gisela D.; Wolfenstein‐Todel, Carlota

doi:10.1016/0167-4838(95)00260-x

Cited by 8 publications

(3 citation statements)

References 26 publications

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“…If 3-aminotyrosine does affect enzyme activity, it might be because of an additional amino functional group which protonates with a pK a of 4.5 (34) and has the potential for additional hydrogen-bonding and electrostatic interactions. The amination of tyrosine in ribonuclease A decreased enzymatic activity by 95%, in R-amylase by 46%, and in ovine placental lactogen by 70% (35)(36)(37). However, speculations regarding the possible biological effects of secondary nitroalkane-induced tyrosine amination must be tempered by the observation that this modification occurs at a frequency of less than 2 residues/1000 tyrosine residues in the liver cytosol of 2-nitropropane-treated rats (Table 3).…”

Section: Discussionmentioning

confidence: 99%

Amination of Tyrosine in Liver Cytosol Protein of Male F344 Rats Treated with 2-Nitropropane, 2-Nitrobutane, 3-Nitropentane, or Acetoxime

Sodum

Fiala

1997

Chem. Res. Toxicol.

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Previously, the secondary nitroalkane 2-nitropropane, a strong hepatocarcinogen in rats, had been shown to induce the formation of 8-aminoguanine in both DNA and RNA of rat liver through a sulfotransferase-mediated pathway. This pathway was postulated to convert the carcinogen into an aminating species [Sodum, R. S., et al. (1994) Chem. Res. Toxicol. 7, 344-351]. To submit this postulate to further test, we examined liver proteins of rats treated with 2-nitropropane, other carcinogenic secondary nitroalkanes, or the related rat liver tumorigen acetoxime for the presence of 3-aminotyrosine, the expected product of tyrosine amination. Using ion-pair and/or cation-exchange high-performance liquid chromatography with electrochemical detection, we found that the liver cytosolic proteins of these animals contained 0.1-1.5 mol of 3-aminotyrosine/10(3) mol of tyrosine. Treatment with the noncarcinogenic primary nitroalkane 1-nitropropane or with other primary nitroalkanes did not produce an analogous increase in the aminated amino acid (level of detection estimated at approximately 0.01 mol/10(3) mol of tyrosine). To our knowledge, this is the first report of the modification of protein tyrosine in vivo by a carcinogen. In vitro studies with acetoxime-O-sulfonate and hydroxylamine-O-sulfonate showed that these proposed intermediates in the activation pathway of 2-nitropropane react with guanosine to give 8-aminoguanosine, N1-aminoguanosine, and 8-oxoguanosine and also react with tyrosine to give 3-aminotyrosine and 3-hydroxytyrosine. The in vitro amination and oxidation of guanosine at C8 were also produced by acetophenoxime-O-sulfonate and 2-heptanoxime-O-sulfonate. These results provide additional evidence for the production of a reactive species capable of aminating nucleic acids and proteins from 2-nitropropane and other carcinogenic secondary nitroalkanes by a pathway involving oxime- and hydroxylamine-O-sulfonates as intermediates.

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Section: Discussionmentioning

confidence: 99%

Amination of Tyrosine in Liver Cytosol Protein of Male F344 Rats Treated with 2-Nitropropane, 2-Nitrobutane, 3-Nitropentane, or Acetoxime

Sodum

Fiala

1997

Chem. Res. Toxicol.

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“…as described previously (Cymes & Wolfenstein-Todel, 1996b). The purity of the protein was ascertained by SDS-PAGE (Laemmli, 1970), where only a single band was apparent.…”

Section: Methodsmentioning

confidence: 99%

Detection and characterization of an ovine placental lactogen stable intermediate in the urea‐induced unfolding process

et al. 1996

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The urea-induced equilibrium unfolding of ovine placental lactogen, purified from ovine placenta, was followed by size-exclusion chromatography, far-UV CD, and intrinsic tryptophan fluorescence. The data obtained by each of these methods showed a poor fit to a two-state model involving only a native and an unfolded form. A satisfactory fit required, instead, a model that involved a stable, partially folded form in addition to the native and unfolded ones. The results obtained from the best-fitting theoretical curves for the three-state model indicated that this intermediate state, which is the predominant species in solution at 3.6 M of urea activity, is compact, largely a-helical, and changes considerably the native-like tertiary packing around its tryptophan residues. These findings suggest that this stable intermediate exhibits properties similar to those that characterize the molten globule state.

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“…The nitrotyrosines are formed by a freeradical mechanism [16] and have an increased absorbance at 430 nm, although the fluorescence properties of tyrosine residues are lost. TNM has also been widely used as tool for studying the role of tyrosine residues in protein complex formation [17][18][19].…”

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confidence: 99%

Studies on a single immunoglobulin-binding domain of protein L from Peptostreptococcus magnus: the role of tyrosine-53 in the reaction with human IgG

Beckingham

Housden

Muir

et al. 2001

Biochemical Journal

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Chemical modification experiments with tetranitromethane (TNM) have been used to investigate the role of tyrosine residues in the formation of the complex between PpL (the single Igbinding domain of protein L, isolated from P. magnus strain 3316) and the kappa light chain (κ-chain). Reaction of PpL with TNM causes the modification of 1.9 equiv. of tyrosine (Tyr&" and Tyr&$) and results in an approx. 140-fold decrease in affinity for human IgG. Similar experiments with mutated PpL proteins suggest that nitration predominantly inactivates the protein by modification of Tyr&$. Reduction of the nitrotyrosine groups to aminotyrosine by incubation with sodium hydrosulphite does not restore high affinity for IgG. Modification of κ-chain by TNM resulted in the nitration of 3.1p0.09 tyrosine residues. When the PpL-κ-chain complex was incubated with TNM,

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Identification of a tyrosine residue in ovine placental lactogen as essential for its binding to receptors

Cited by 8 publications

References 26 publications

Amination of Tyrosine in Liver Cytosol Protein of Male F344 Rats Treated with 2-Nitropropane, 2-Nitrobutane, 3-Nitropentane, or Acetoxime

Amination of Tyrosine in Liver Cytosol Protein of Male F344 Rats Treated with 2-Nitropropane, 2-Nitrobutane, 3-Nitropentane, or Acetoxime

Detection and characterization of an ovine placental lactogen stable intermediate in the urea‐induced unfolding process

Studies on a single immunoglobulin-binding domain of protein L from Peptostreptococcus magnus: the role of tyrosine-53 in the reaction with human IgG

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