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Characterization of Cys-34 in serum albumin

Tong, Grace C.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1061473878

Abstract Details

2003, Doctor of Philosophy, Ohio State University, Biochemistry.
The Cys-34 thiol of serum albumin has been suggested to be a carrier and stabilizer of nitric oxide in plasma. The pKa of the Cys-34 thiol of serum albumins from human, bovine, equine, and canine species were determined kinetically and spectroscopically by following the absorbance of the thiolate anion. All serum albumins gave pKa’s of ~8.5 for their Cys-34 thiols. The reactions between serum albumin and its model compounds, glutathione and N-acetyltryptiophan, with fast acting vasodilating drugs, sodium nitroprusside and isoamylnitrite, and with sodium nitrite were studied. It was found that the reactions with serum albumin are too slow to account for the immediate physiological effects of these compounds; serum albumin probably participate in their hypotensive effects indirectly through nitrosation by S-nitrosothiols formed in plasma. The rate of oxidation and reduction reactions for Cys-34 reacting with various disulfides and thiols commonly found in plasma were measured. The thiol content of bovine and human serum albumin (BSA and HSA) obtained from various sources, and HSA from freshly isolated plasma were also measured. The thiol contents of commercial preparations of HSA were only a fraction compared to those of HSA in fresh plasma and of BSA. The rates of Michael addition reactions between acrylamide, a neurotoxin recently discovered to be present in many common foods, and GSH and Cys-34 of HSA, were measured under physiological conditions. The half-life of acrylamide in blood was calculated to be < 7 hours. The mechanism of fatty acid binding as well as the influence of that on the reactivity of Cys-34 was examined. The cooperative binding of 4 to 5 molecules of fatty acids to each serum albumin was concluded from results of kinetic and mass analyses. It was also found that Cys-34 became more reactive upon fatty acid binding. This is presumed to be due to a conformational change that causes the enlargment of the Cys-34 cavity.
Gary Means (Advisor)
225 p.
acrylamide; cooperative binding; cys-34; fatty acid binding; nitric oxide; nitrosation of cysteine; nitrosation of tryptophan; redox state of thiol; pKa of protein thiol; serum albumin; S-nitrosothiol; thiol reactivity

Recommended Citations

Citations

  • Tong, G. C. (2003). Characterization of Cys-34 in serum albumin [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1061473878

    APA Style (7th edition)

  • Tong, Grace. Characterization of Cys-34 in serum albumin. 2003. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1061473878.

    MLA Style (8th edition)

  • Tong, Grace. "Characterization of Cys-34 in serum albumin." Doctoral dissertation, Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1061473878

    Chicago Manual of Style (17th edition)

osu1061473878
6,852
© 2003, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.