Effect of free fatty acids on the binding kinetics at the benzodiazepine binding site of glycated human serum albumin.
The effect of free fatty acids (FFA) and non-enzymatic glycation on the binding kinetics of dansylsarcosine (DS) to human serum albumin (HSA) was studied using the stopped-flow technique. The influence of FFA on the binding parameters of 25% glycated HSA depended on the type of fatty acid. The addition of stearic, oleic and linoleic acids in a concentration of 0.3 mmol/l showed no inhibitory effects on the association rate constant (k2) value for DS binding to 25% glycated HSA (k2 without FFA: 385 +/- 10 s-1, k2 with FFA > or = 385 +/- 10 s-1). In contrast, shorter chain fatty acids (hexanoic, octanoic, decanoic, lauric and myristic acids) showed marked inhibitory effects for 0.3 mmol/l FFA (k2 range: 233 +/- 32 to 69 +/- 5 s-1) and for 0.6 mmol/l FFA (k2 range: 125 +/- 3 to 20 +/- 4 s-1). The association rate constant (k2) as well as the affinity constant (KA) of DS were markedly affected by glycation: k2 was 686 +/- 61 s-1 for 7% glycated HSA, 385 +/- 10 s-1 for 25% glycated HSA and 209 +/- 12 s-1 for 50% glycated HSA. KA decreased from 6.1 +/- 2.9 x 10(5) M-1 for 7% glycated HSA, to 5.1 +/- 0.1 x 10(5) M-1 for 25% glycated HSA and to 1.3 +/- 0.6 x 10(5) M-1 for 50% glycated HSA.(ABSTRACT TRUNCATED AT 250 WORDS)
Keita
Y
Y
Department of Clinical Pharmacology, Johann Wolfgang Goethe University Clinic, Frankfurt/Main, Germany.
Kratzer
W
W
Wörner
W
W
Rietbrock
N
N
D001569:Benzodiazepines / Q000737:chemistry*; D003619:Dansyl Compounds / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005230:Fatty Acids, Nonesterified / Q000378:metabolism / Q000494:pharmacology*; D017127:Glycation End Products, Advanced; D006031:Glycosylation; D006801:Humans; D007700:Kinetics; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000494:pharmacology; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D012521:Sarcosine / Q000031:analogs & derivatives / Q000378:metabolism; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D013229:Stearic Acids / Q000494:pharmacology; D000093423:Glycated Serum Albumin
D003619:Dansyl Compounds; D005230:Fatty Acids, Nonesterified; D017127:Glycation End Products, Advanced; D008041:Linoleic Acids; D009829:Oleic Acids; D012709:Serum Albumin; D013229:Stearic Acids; C037087:dansylsarcosine; D001569:Benzodiazepines; D019301:Oleic Acid; C031183:stearic acid; D019787:Linoleic Acid; D012521:Sarcosine; D000093423:Glycated Serum Albumin