Premium
Kinetic studies on the inhibition of creatine kinase activity by branched‐chain α‐amino acids in the brain cortex of rats
Author(s) -
Pilla Carmen,
Oliveira Cardozo Rui Felipe,
Dornelles Paula Karine Barcelos,
DutraFilho Carlos Severo,
Souza Wyse Angela Terezinha,
Wajner Moacir,
Wannmacher Clóvis Milton Duval
Publication year - 2003
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/s0736-5748(03)00028-5
Subject(s) - maple syrup urine disease , creatine , creatine kinase , phosphocreatine , amino acid , enzyme , biochemistry , medicine , endocrinology , homeostasis , branched chain amino acid , energy homeostasis , metabolism , chemistry , biology , energy metabolism , leucine , receptor
Maple syrup urine disease (MSUD) is a metabolic disorder biochemically characterized by the accumulation of branched‐chain α‐amino acids (BCAA) and their branched‐chain α‐keto acids (BCKA) in blood and tissues. Neurological dysfunction is usually present in the patients, but the mechanisms of brain damage in this disease are far from be understood. The main objective of this study was to investigate the mechanisms by which BCAA inhibit creatine kinase activity, a key enzyme of energy homeostasis, in the brain cortex of 21‐day‐old Wistar rats. For the kinetic studies, Lineweaver–Burk and a modification of the Chevillard et al. plots were used to characterize the mechanisms of enzyme inhibition. The results indicated that BCAA inhibit creatine kinase by competition with the substrates phosphocreatine and ADP at the active site. Considering the crucial role creatine kinase plays in energy homeostasis in brain, if these effects also occur in the brain of MSUD patients, it is possible that inhibition of this enzyme activity may contribute to the brain damage found in this disease. In this case, it is possible that creatine supplementation to the diet might benefit MSUD patients.