TY - JOUR
T1 - Comparison of modification sites formed on human serum albumin at various stages of glycation
AU - Barnaby, Omar S.
AU - Cerny, Ronald L.
AU - Clarke, William
AU - Hage, David S.
N1 - Funding Information:
This research was supported by the National Institute of Health (NIH) under grant R01 DK069629 . Support for the remodeled facilities used to perform these experiments was provided by NIH grant RR015468-001 . Part of this work was carried out in the Nebraska Center for Mass Spectrometry, as supported by the National Cancer Institute under grant P30 CA36727 , the NIH under grants P20 RR15635 and RR015468 , and the Nebraska Research Initiative .
PY - 2011/1/30
Y1 - 2011/1/30
N2 - Background: Many of the complications encountered during diabetes can be linked to the non-enzymatic glycation of proteins, including human serum albumin (HSA). However, there is little information regarding how the glycation pattern of HSA changes as the total extent of glycation is varied. The goal of this study was to identify and conduct a semi-quantitative comparison of the glycation products on HSA that are produced in the presence of various levels of glycation. Methods: Three glycated HSA samples were prepared in vitro by incubating physiological concentrations of HSA with 15. mmol/l glucose for 2 or 5. weeks, or with 30. mmol/l glucose for 4. weeks. These samples were then digested and examined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the glycation products that were formed. Results: It was found that the glycation pattern of HSA changed with its overall extent of total glycation. Many modifications including previously-reported primary glycation sites (e.g., K199, K281, and the N-terminus) were consistently found in the tested samples. Lysines 199 and 281, as well as arginine 428, contained the most consistently identified and abundant glycation products. Lysines 93, 276, 286, 414, 439, and 524/525, as well as the N-terminus and arginines 98, 197, and 521, were also found to be modified at various degrees of HSA glycation. Conclusions: The glycation pattern of HSA was found to vary with different levels of total glycation and included modifications at the 2 major drug binding sites on this protein. This result suggests that different modified forms of HSA, both in terms of the total extent of glycation and glycation pattern, may be found at various stages of diabetes. The clinical implication of these results is that the binding of HSA to some drug may be altered at various stages of diabetes as the extent of glycation and types of modifications in this protein are varied.
AB - Background: Many of the complications encountered during diabetes can be linked to the non-enzymatic glycation of proteins, including human serum albumin (HSA). However, there is little information regarding how the glycation pattern of HSA changes as the total extent of glycation is varied. The goal of this study was to identify and conduct a semi-quantitative comparison of the glycation products on HSA that are produced in the presence of various levels of glycation. Methods: Three glycated HSA samples were prepared in vitro by incubating physiological concentrations of HSA with 15. mmol/l glucose for 2 or 5. weeks, or with 30. mmol/l glucose for 4. weeks. These samples were then digested and examined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the glycation products that were formed. Results: It was found that the glycation pattern of HSA changed with its overall extent of total glycation. Many modifications including previously-reported primary glycation sites (e.g., K199, K281, and the N-terminus) were consistently found in the tested samples. Lysines 199 and 281, as well as arginine 428, contained the most consistently identified and abundant glycation products. Lysines 93, 276, 286, 414, 439, and 524/525, as well as the N-terminus and arginines 98, 197, and 521, were also found to be modified at various degrees of HSA glycation. Conclusions: The glycation pattern of HSA was found to vary with different levels of total glycation and included modifications at the 2 major drug binding sites on this protein. This result suggests that different modified forms of HSA, both in terms of the total extent of glycation and glycation pattern, may be found at various stages of diabetes. The clinical implication of these results is that the binding of HSA to some drug may be altered at various stages of diabetes as the extent of glycation and types of modifications in this protein are varied.
KW - Diabetes
KW - Glycation-related modifications
KW - Human serum albumin
KW - Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
KW - Non-enzymatic glycation
UR - http://www.scopus.com/inward/record.url?scp=78650250717&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=78650250717&partnerID=8YFLogxK
U2 - 10.1016/j.cca.2010.10.018
DO - 10.1016/j.cca.2010.10.018
M3 - Article
C2 - 21034726
AN - SCOPUS:78650250717
SN - 0009-8981
VL - 412
SP - 277
EP - 285
JO - Clinica Chimica Acta
JF - Clinica Chimica Acta
IS - 3-4
ER -