Abstract
The interaction of various anions with human serum transferrin was investigated due to the concomitant binding of iron and a synergistic anion to form the transferrin-anion-iron complex. Two tetrahedral oxyanion oxidizing agents, periodate and permanganate, were found to partially inactivate transferrin when used at equimolar ratios of oxidizing agent to protein active sites. Hypochlorite, a strong oxidizing agent with little structural similarity to periodate and permanganate, had little effect on iron-binding activity when used at similar low molar ratios of reagent to transferrin active sites. Transferrin treated with a 3:1 molar ratio of periodate or permanganate to active sites lost 74 or 67% of its iron-binding capacity, respectively. The composition of the buffer affected the extent of transferrin inactivation by periodate and permanganate; for example, the extent of inactivation by periodate was threefold greater in a borate buffer than in a phosphate buffer. Comparative oxidations in buffer systems suggest the following order of affinity of three buffer anions for the apotransferrin metal-binding center: phosphate > bicarbonate > borate. The interaction of phosphate ions with the iron-transferrin complex was also examined due to the increased susceptibility to periodate inactivation of iron-saturated transferrin in phosphate buffer (M. H. Penner, R. B. Yamasaki, D. T. Osuga, D. R. Babin, C. F. Meares, and R. E. Feeney (1983) Arch. Biochem. Biophys. 225, 740-747). The apparent destabilization of the iron-transferrin complex in phosphate buffer was found to be due to the competitive removal of iron by phosphate from the iron-protein complex. We found that phenylglyoxal-modified Fe-transferrin, with no loss of bound iron, was much more resistant to iron removal by phosphate and other competitive chelators.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 7-14 |
| Number of pages | 8 |
| Journal | Archives of Biochemistry and Biophysics |
| Volume | 252 |
| Issue number | 1 |
| DOIs | |
| State | Published - 1987 |
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ASJC Scopus subject areas
- Biochemistry
- Biophysics
- Molecular Biology
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The interaction of anions with native and phenylglyoxal-modified human serum transferrin. / Penner, Michael H.; Osuga, David T.; Meares, Claude F.; Feeney, Robert E.
In: Archives of Biochemistry and Biophysics, Vol. 252, No. 1, 1987, p. 7-14.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The interaction of anions with native and phenylglyoxal-modified human serum transferrin
AU - Penner, Michael H.
AU - Osuga, David T.
AU - Meares, Claude F.
AU - Feeney, Robert E.
PY - 1987
Y1 - 1987
N2 - The interaction of various anions with human serum transferrin was investigated due to the concomitant binding of iron and a synergistic anion to form the transferrin-anion-iron complex. Two tetrahedral oxyanion oxidizing agents, periodate and permanganate, were found to partially inactivate transferrin when used at equimolar ratios of oxidizing agent to protein active sites. Hypochlorite, a strong oxidizing agent with little structural similarity to periodate and permanganate, had little effect on iron-binding activity when used at similar low molar ratios of reagent to transferrin active sites. Transferrin treated with a 3:1 molar ratio of periodate or permanganate to active sites lost 74 or 67% of its iron-binding capacity, respectively. The composition of the buffer affected the extent of transferrin inactivation by periodate and permanganate; for example, the extent of inactivation by periodate was threefold greater in a borate buffer than in a phosphate buffer. Comparative oxidations in buffer systems suggest the following order of affinity of three buffer anions for the apotransferrin metal-binding center: phosphate > bicarbonate > borate. The interaction of phosphate ions with the iron-transferrin complex was also examined due to the increased susceptibility to periodate inactivation of iron-saturated transferrin in phosphate buffer (M. H. Penner, R. B. Yamasaki, D. T. Osuga, D. R. Babin, C. F. Meares, and R. E. Feeney (1983) Arch. Biochem. Biophys. 225, 740-747). The apparent destabilization of the iron-transferrin complex in phosphate buffer was found to be due to the competitive removal of iron by phosphate from the iron-protein complex. We found that phenylglyoxal-modified Fe-transferrin, with no loss of bound iron, was much more resistant to iron removal by phosphate and other competitive chelators.
AB - The interaction of various anions with human serum transferrin was investigated due to the concomitant binding of iron and a synergistic anion to form the transferrin-anion-iron complex. Two tetrahedral oxyanion oxidizing agents, periodate and permanganate, were found to partially inactivate transferrin when used at equimolar ratios of oxidizing agent to protein active sites. Hypochlorite, a strong oxidizing agent with little structural similarity to periodate and permanganate, had little effect on iron-binding activity when used at similar low molar ratios of reagent to transferrin active sites. Transferrin treated with a 3:1 molar ratio of periodate or permanganate to active sites lost 74 or 67% of its iron-binding capacity, respectively. The composition of the buffer affected the extent of transferrin inactivation by periodate and permanganate; for example, the extent of inactivation by periodate was threefold greater in a borate buffer than in a phosphate buffer. Comparative oxidations in buffer systems suggest the following order of affinity of three buffer anions for the apotransferrin metal-binding center: phosphate > bicarbonate > borate. The interaction of phosphate ions with the iron-transferrin complex was also examined due to the increased susceptibility to periodate inactivation of iron-saturated transferrin in phosphate buffer (M. H. Penner, R. B. Yamasaki, D. T. Osuga, D. R. Babin, C. F. Meares, and R. E. Feeney (1983) Arch. Biochem. Biophys. 225, 740-747). The apparent destabilization of the iron-transferrin complex in phosphate buffer was found to be due to the competitive removal of iron by phosphate from the iron-protein complex. We found that phenylglyoxal-modified Fe-transferrin, with no loss of bound iron, was much more resistant to iron removal by phosphate and other competitive chelators.
UR - http://www.scopus.com/inward/record.url?scp=0023103117&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0023103117&partnerID=8YFLogxK
U2 - 10.1016/0003-9861(87)90002-6
DO - 10.1016/0003-9861(87)90002-6
M3 - Article
C2 - 3028261
AN - SCOPUS:0023103117
VL - 252
SP - 7
EP - 14
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
SN - 0003-9861
IS - 1
ER -