Inhibitory effect of glycation on catalytic activity of alanine aminotransferase
Language English Country Netherlands Media print
Document type Comparative Study, Journal Article, Research Support, Non-U.S. Gov't
- MeSH
- Enzyme Activation drug effects MeSH
- Alanine antagonists & inhibitors MeSH
- Alanine Transaminase metabolism MeSH
- Time Factors MeSH
- Pharmacology MeSH
- Fructose metabolism MeSH
- Glucose metabolism MeSH
- Glyceraldehyde antagonists & inhibitors MeSH
- Catalysis MeSH
- Ketoglutaric Acids metabolism MeSH
- Lysine metabolism MeSH
- Myocardium enzymology MeSH
- Swine MeSH
- Pyridoxal Phosphate MeSH
- Ribose metabolism MeSH
- In Vitro Techniques MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
- Names of Substances
- Alanine MeSH
- Alanine Transaminase MeSH
- Fructose MeSH
- Glucose MeSH
- Glyceraldehyde MeSH
- Ketoglutaric Acids MeSH
- Lysine MeSH
- Pyridoxal Phosphate MeSH
- Ribose MeSH
Non-enzymatic glycation is a common post-translational modification of tissue and plasma proteins which can impair their functions in living organisms. In this study, the authors have demonstrated for the first time an inhibitory effect of in vitro glycation on the catalytic activity of alanine aminotransferase (ALT, EC 2.6.1.2), a pyridoxal phosphate enzyme with several lysine residues in the molecule. The porcine heart enzyme was incubated with 50 mmol/l D-fructose, D-glucose, D,L-glyceraldehyde, or D-ribose in 0.1 mol/l phosphate buffer (pH 7.4) at 25 degrees C for up to 20 days. The strongest glycation effect was shown by D,L-glyceraldehyde, which caused complete enzyme inhibition within 6 days. After 20 days of incubation, the ALT activity in samples with D-fructose and D-ribose was less than 7% of the initial enzyme activity. A statistically significant effect of D-glucose on the enzymatic activity of ALT was not found. Incubation of ALT with D-fructose, D,L-glyceraldehyde and D-ribose minimized its catalytic activity both in the glycated and non-glycated fractions of the samples. Markedly higher activity was found in the glycated fraction with glucose. The inhibitory effect of glycation of ALT with D-fructose and D-ribose was found to be more intensive in the presence of L-alanine and weaker in the presence of 2-oxoglutarate. The findings suggest that glycation of the epsilon-amino group of Lys313 as a crucial part of the catalytic site of ALT may contribute to ALT inactivation in the presence of glycating sugars. Nevertheless, glycation of lysine residues outside the active center of ALT seems to be primary.
See more in PubMed
Hoppe Seylers Z Physiol Chem. 1982 Dec;363(12):1427-36 PubMed
Biochim Biophys Acta. 1987 May 19;924(2):292-6 PubMed
Biochemistry. 1991 Oct 29;30(43):10451-7 PubMed
Science. 1981 Jul 10;213(4504):222-4 PubMed
J Biochem Biophys Methods. 1994 Mar;28(2):115-21 PubMed
J Biol Chem. 1977 Jul 25;252(14):4958-61 PubMed
Chem Pharm Bull (Tokyo). 1987 Jan;35(1):302-7 PubMed
J Nutr Sci Vitaminol (Tokyo). 1993 Aug;39(4):311-21 PubMed
Clin Chim Acta. 1987 Jul 15;166(2-3):227-36 PubMed
Biochemistry. 1991 Jun 18;30(24):6048-53 PubMed
J Nutr Sci Vitaminol (Tokyo). 1997 Aug;43(4):463-9 PubMed
FEBS Lett. 1975 Apr 15;53(1):29-32 PubMed
J Biol Chem. 1975 Oct 25;250(20):7961-7 PubMed
Clin Chem. 1987 Oct;33(10):1807-10 PubMed
Eur J Biochem. 1978 Aug 1;88(2):467-73 PubMed
Comparison of glycation of glutathione S-transferase by methylglyoxal, glucose or fructose
