Possible involvement of glutamic and/or aspartic acid residue(s) and requirement of mitochondrial integrity for the protective effect of creatine against inhibition of cardiac mitochondrial respiration by methylglyoxal.
We had previously shown that creatine exerted a protective effect against inhibition of cardiac mitochondrial respiration by methylglyoxal (SinhaRoy S, Biswas S, Ray M, Ray S. Biochem J 372: 661-669,2003). In the present study, we have investigated the mechanism of this protective effect by specific amino acid modifying reagent and by several compounds, which are structurally related to creatine. The results show that the compounds, which contain guanidine group such as arginine and guanidinopropionic acid, exert a protective effect, which is quantitatively similar to creatine. This result suggests the presence of carboxylic acid(s) such as glutamic and/or aspartic acid(s) in the creatine-binding site, which has been further supported by experiments with N-ethyl-5-phenyl isoxazolium-3'-sulfonate a reagent known to modify these amino acids. Both polarographic and spectrophotometric assays were performed with NADH as respiratory substrate by using a) submitochondrial particles by sonication, b) freeze-thawed mitochondria and c) mitochondria permeabilized by alamethicin treatment. The results of these studies as compared to that of intact mitochondria indicate that structural integrity of mitochondria is essential for the protective effect of creatine.
SinhaRoy
Soumya
S
Department of Biological Chemistry, India Associationfor the Cultivation of Science, Jadavpur, Kolkata - 700 032, India.
Banerjee
Sambhunath
S
Ray
Manju
M
Ray
Subhankar
S
D000408:Alamethicin / Q000494:pharmacology; D000818:Animals; D001224:Aspartic Acid / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D019069:Cell Respiration / Q000187:drug effects; D003401:Creatine / Q000031:analogs & derivatives / Q000494:pharmacology*; D042967:Electron Transport Complex I / Q000187:drug effects / Q000378:metabolism; D018698:Glutamic Acid / Q000737:chemistry / Q000378:metabolism*; D006041:Goats; D007425:Intracellular Membranes / Q000187:drug effects; D007555:Isoxazoles / Q000494:pharmacology; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009245:NADH Dehydrogenase / Q000187:drug effects / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D010539:Permeability / Q000187:drug effects; D020011:Protective Agents / Q000494:pharmacology*; D011765:Pyruvaldehyde / Q000009:adverse effects; D013367:Submitochondrial Particles / Q000187:drug effects / Q000378:metabolism
D007555:Isoxazoles; D020011:Protective Agents; D009243:NAD; D000408:Alamethicin; D001224:Aspartic Acid; C009686:N-ethyl-5-phenylisoxazolium-3'-sulfonate; D018698:Glutamic Acid; D011765:Pyruvaldehyde; D009245:NADH Dehydrogenase; D042967:Electron Transport Complex I; D003401:Creatine