scholarly journals Chromatographic assay of glycation adducts in human serum albumin glycated in vitro by derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl-carbamate and intrinsic fluorescence

2002 ◽  
Vol 364 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Naila AHMED ◽  
Paul J. THORNALLEY

Glycation of proteins leads to the formation of advanced glycation endproducts (AGEs) of diverse molecular structure and biological function. Serum albumin derivatives modified to minimal and high extents by methylglyoxal and glucose in vitro have been used in many studies as model AGE proteins. The early and advanced glycation adduct contents of these proteins were investigated using the 6-aminoquinolyl-N-hydroxysuccinimidyl-carbamate (AQC) chromatographic assay of enzymic hydrolysates. AGEs derived from methylglyoxal, glyoxal and 3-deoxyglucosone, the hydroimidazolones Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1), Nδ-(5-hydro-4-imidazolon-2-yl)ornithine (G-H1) and Nδ-[5-(2,3,4-trihydroxybutyl)-5-hydro-4-imidazolon-2-yl]ornithine (3DG-H1), bis(lysyl)imidazolium cross-links methylglyoxal-derived lysine dimer (MOLD), glyoxal-derived lysine dimer (GOLD), 3-deoxyglucosone-derived lysine dimer (DOLD), monolysyl adducts N∊-(1-carboxyethyl)lysine (CEL), N∊-carboxymethyl-lysine (CML) and pyrraline, other AGEs, Nδ-(4-carboxy-4,6-dimethyl-5,6-dihydroxy-1,4,5,6-tetrahydropyrimidin-2-yl)ornithine (THP), argpyrimidine and pentosidine, and fructosyl-lysine were determined. AGEs with intrinsic fluorescence (argpyrimidine and pentosidine) were assayed without derivatization. Human serum albumin (HSA) glycated minimally by methylglyoxal in vitro contained mainly MG-H1 with minor amounts of THP and argpyrimidine. Similar AGEs were found in prothrombin glycated minimally by methylglyoxal and in Nα-t-butyloxycarbonyl-arginine incubated with methylglyoxal. HSA glycated highly by methylglyoxal contained mainly argpyrimidine, MG-H1 and THP, with minor amounts of CEL and MOLD. HSA glycated minimally by glucose in vitro contained mainly fructosyl-lysine and CML, with minor amounts of THP, MG-H1, G-H1, 3DG-H1, argpyrimidine and DOLD. HSA glycated highly by glucose contained these AGEs and pyrraline, and very high amounts (≈8mol/mol of protein) of fructosyl-lysine. Most AGEs in albumin glycated minimally by methylglyoxal and glucose were identified. Significant proportions of arginine and lysine-derived AGEs in albumin modified highly by methylglyoxal, and lysine-derived AGEs in albumin modified highly by glucose, remain to be identified.

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 474 ◽  
Author(s):  
Carolina Luna ◽  
Alexis Arjona ◽  
Carmen Dueñas ◽  
Mario Estevez

Understanding the molecular basis of the disease is of the utmost scientific interest as it contributes to the development of targeted strategies of prevention, diagnosis, and therapy. Protein carbonylation is a typical feature of glyco-oxidative stress and takes place in health disorders such as diabetes. Allysine as well as its oxidation product, the α-amino adipic acid (α-AA) have been found to be markers of diabetes risk whereas little is known about the chemistry involved in its formation under hyperglycemic conditions. To provide insight into this issue, human serum albumin was incubated in the presence of FeCl3 (25 μM) and increasing glucose concentrations for 32 h at 37 °C. These concentrations were selected to simulate (i) physiological fasting plasma concentration (4 mM), (ii) pathological pre-diabetes fasting plasma concentration (8 mM), and pathological diabetes fasting plasma concentration (12 mM) of glucose. While both allysine and α-AA were found to increase with increasing glucose concentrations, the carboxylic acid was only detected at pathological glucose concentrations and appeared to be a more reliable indicator of glyco-oxidative stress. The underlying chemical mechanisms of lysine glycation as well as of the depletion of tryptophan and formation of fluorescent and colored advanced glycation products are discussed.


2021 ◽  
pp. 116888
Author(s):  
Fahad A. Alhumaydhi ◽  
Mohammad Abdullah Aljasir ◽  
Abdullah S.M. Aljohani ◽  
Suliman A. Alsagaby ◽  
Ameen S.S. Alwashmi ◽  
...  

2020 ◽  
Vol 14 (1) ◽  
pp. 22
Author(s):  
Kenji Tsukigawa ◽  
Shuhei Imoto ◽  
Keishi Yamasaki ◽  
Koji Nishi ◽  
Toshihiko Tsutsumi ◽  
...  

In a previous study, we reported on the development of a synthetic polymer conjugate of pirarubicin (THP) that was formed via an acid-labile hydrazone bond between the polymer and the THP. However, the synthetic polymer itself was non-biodegradable, which could lead to unexpected adverse effects. Human serum albumin (HSA), which has a high biocompatibility and good biodegradability, is also a potent carrier for delivering antitumor drugs. The objective of this study was to develop pH-sensitive HSA conjugates of THP (HSA-THP), and investigate the release of THP and the cytotoxicity under acidic conditions in vitro for further clinical development. HSA-THP was synthesized by conjugating maleimide hydrazone derivatives of THP with poly-thiolated HSA using 2-iminothiolane, via a thiol-maleimide coupling reaction. We synthesized two types of HSA-THP that contained different amounts of THP (HSA-THP2 and HSA-THP4). Free THP was released from both of the HSA conjugates more rapidly at an acidic pH, and the rates of release for HSA-THP2 and HSA-THP4 were similar. Moreover, both HSA-THPs exhibited a higher cytotoxicity at acidic pH than at neutral pH, which is consistent with the effective liberation of free THP under acidic conditions. These findings suggest that these types of HSA-THPs are promising candidates for further development.


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