Non-additive counteraction of KCl-perturbation of lactate dehydrogenase by trimethylamine N-oxide.
Added KCl increases the apparent Michaelis constant (Km) of pyruvate for porcine muscle-type lactate dehydrogenase (100 mM KCl, 83%; 200 mM KCl, 188%). The effects of 100 mM KCl were fully reversed by 375 mM trimethylamine N-oxide (TMAO). TMAO (375-750 mM) partially reversed the effects of 200 mM KCl. TMAO as the sole solute, at concentrations up to 750 mM, had no effect on Km. This is atypical because compensatory osmolytes such as TMAO characteristically counteract protein perturbation in an additive manner.
Desmond
Matthew K
MK
Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
Siebenaller
Joseph F
JF
D000818:Animals; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008744:Methylamines / Q000737:chemistry / Q000494:pharmacology*; D008958:Models, Molecular; D009132:Muscles / Q000201:enzymology; D016877:Oxidants / Q000494:pharmacology; D011189:Potassium Chloride / Q000737:chemistry / Q000494:pharmacology*; D013552:Swine
D008744:Methylamines; D016877:Oxidants; D011189:Potassium Chloride; D007770:L-Lactate Dehydrogenase; C005855:trimethyloxamine