Human serum albumin

About: Human serum albumin is a research topic. Over the lifetime, 9402 publications have been published within this topic receiving 269029 citations. The topic is also known as: serum albumin & ALB.

Studies on the mechanism of binding of serum albumins to immobilized cibacron blue F3G A

Abstract: The interaction of Cibacron Blue F3G A-Sepharose 4B with several serum albumins was studied. Although all albumins used were fond to bind to this adsorbent, human serum albumin was bound to a far greater extent than were the others. From the results of competition experiments and n.m.r. studies of Cibacron Blue and/or bilirubin binding to human serum albumin it is proposed that the mechanism of the interaction between human serum albumin and cibacron Blue is consistent wit Cibacron Blue binding to bilirubin-binding sites. In contrast with these findings with human serum albumin, there is little or no interaction of Cibacron Blue and the bilirubin-binding sites of albumins from rabbit, horse, bovine or sheep sera, although some interaction occurs between Cibacron Blue and the fatty acid-binding sites of these proteins. Structural analogues of Cibacron Blue have been used to investigate the binding of albumins to these ligands.

Marked interspecies variations concerning the interactions of camptothecin with serum albumins: a frequency-domain fluorescence spectroscopic study.

Abstract: Camptothecin, an anticancer agent reknown for its novel mechanism of action and outstanding murine in vivo activity, has to date displayed only modest therapeutic utility against human cancers. The drug contains an delta-lactone ring moiety which, at pH7.4, hydrolyzes to yield a biologically inactive carboxylate form. Comparison of drug stability in both plasma and purified serum albumin samples revealed that ring opening occurred to a much greater extent in human samples versus those of other species. Multifrequency phase-modulation spectroscopic analyses of the intrinsic fluorescence emissions of the two drug forms revealed a physical explanation for the extensive ring opening observed in the presence of human serum albumin (HSA): the protein exhibited a marked 200-fold binding preference for the carboxylate (K = 1.2 x 10(6) M-1) relative to the lactone (K approximately 5.5 x 10(3) M-1). Serum albumins from other species were found to bind camptothecin carboxylate not nearly as tightly as HSA. Due to the unique capacity of human albumin to bind camptothecin carboxylate, resulting in extensive conversion of the drug to its biologically inactive form, it appears that the success of the agent in eradicating cancer in animal models may be inherently more difficult to duplicate in man.

Masticatory lubrication. The role of carbohydrate in the lubricating property of a salivary glycoprotein-albumin complex.

Abstract: We report for the first time a masticatory-lubrication assay system to assess the lubricating properties of salivary constituents. The lubricating ability of the proline-rich glycoprotein (PRG) of parotid saliva was enhanced by human serum albumin. The interactive effect of albumin was abolished by chemically deglycosylating the glycoprotein. Fluorescence spectroscopy with a hydrophobic probe verified the existence of a PRG-albumin complex and demonstrated that deglycosylation of the PRG altered the nature of its interaction with albumin.

Separation of sublethal and lethal effects of the bactericidal/permeability increasing protein on Escherichia coli.

Abstract: Binding of the bactericidal/permeability increasing protein (BPI) of granulocytes to Escherichia coli promptly produces several discrete outer envelope alterations and growth arrest without major impairment of bacterial structure or biosynthetic capabilities, raising the question whether these early effects of BPI are sufficient to cause bacterial death. In this study, the bactericidal action of BPI was examined more closely. We have found that bovine or human serum albumin blocks bacterial killing without preventing BPI binding or an increase in outer membrane permeability. Moreover, addition of serum albumin after BPI results in growth resumption without displacement of bound BPI and without (early) repair of the envelope alterations. These effects are opposite to those produced by Mg2+ (80 mM), which displaces greater than 85% of bound BPI and rapidly initiates outer envelope repair without restoration of bacterial growth. The extent of rescue by serum albumin depends on the time and pH of preincubation of BPI with E. coli: e.g., for E. coli J5 treated with human BPI, t1/2 = 79 min at pH 7.4 and 10 min at pH 6.0. The serum albumin effects on BPI action are the same in wild-type E. coli and in a mutant strain lacking an activatable phospholipase, indicating that serum albumin does not act by sequestering membrane-damaging products of bacterial phospholipid hydrolysis. The progression from reversible to irreversible growth arrest, revealed by the subsequent addition of serum albumin at different times, is paralleled by a decrease in amino acid uptake and an increase in the permeability of the cytoplasmic membrane to o-nitrophenyl-beta-D-galactoside. These findings demonstrate at least two stages in the action of BPI: (a) an early, reversible, sublethal stage in which BPI has effects on the outer envelope and causes growth arrest, and (b) time- and pH-dependent progression to a lethal stage, apparently involving cytoplasmic membrane damage, possibly caused by penetration of a small subpopulation of BPI.