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Proceedings Paper

Fluorescence lifetime measurements of native and glycated human serum albumin and bovine serum albumin
Author(s): Narahari V. Joshi; Virgina Otero de Joshi; Silvia Contreras; Herminia Gil; Honorio Medina; Aleksander Siemiarczuk
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Paper Abstract

Nonenzymatic glycation, also known as Maillard reaction, plays an important role in the secondary complications of the diabetic pathology and aging, therefore, human serum albumin (HSA) and bovine serum albumin (BSA) were glycated by a conventional method in our laboratory using glucose as the glycating agent. Fluorescence lifetime measurements were carried out with a laser strobe fluorometer equipped with a nitrogen/dye laser and a frequency doubler as a pulsed excitation source. The samples were excited at 295 nm and the emission spectra were recorded at 345 nm. The obtained decay curves were tried for double and triple exponential functions. It has been found that the shorter lifetime increases for glycated proteins as compared with that of the native ones. For example, in the case of glycated BSA the lifetime increased from 1.36 ns to 2.30 ns. Similarly, for HSA, the lifetime increases from 1.58 ns to 2.26 ns. Meanwhile, the longer lifetime changed very slightly for both proteins (from 6.52 ns to 6.72 ns). The increase in the lifetime can be associated with the environmental effect; originated from the attachment of glucose to some lysine residues. A good example is Trp 214 which is in the cage of Lys 225, Lys 212, Lys 233, Lys 205, Lys 500, Lys 199 and Lys 195. If fluorescence lifetime technique is calibrated and properly used it could be employed for assessing glycation of proteins.

Paper Details

Date Published: 3 May 1999
PDF: 8 pages
Proc. SPIE 3602, Advances in Fluorescence Sensing Technology IV, (3 May 1999); doi: 10.1117/12.347514
Show Author Affiliations
Narahari V. Joshi, Univ. of Los Andes (Spain)
Virgina Otero de Joshi, Univ. of Los Andes (Venezuela)
Silvia Contreras, Univ. of Los Andes (Venezuela)
Herminia Gil, Univ. of Los Andes (Venezuela)
Honorio Medina, Univ. of Los Andes (Venezuela)
Aleksander Siemiarczuk, Photon Technology International, Inc. (Canada)

Published in SPIE Proceedings Vol. 3602:
Advances in Fluorescence Sensing Technology IV
Joseph R. Lakowicz; Steven A. Soper; Richard B. Thompson, Editor(s)

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