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The binding of coenzyme and substrate are considered in relation to the known primary and tertiary structure of lactate dehydrogenase (EC 1.1.1.27). The adenine binds in a hydrophobic crevice, and the two coenzyme phosphates are oriented by interactions with the protein. The positively charged guanidinium group of arginine 101 then folds over the negatively(More)
A proton-translocating ATPase was identified in highly purified lysosomes from Epstein-Barr virus-transformed human lymphoblasts. Activity of this ATPase caused acidification of highly purified, fluorescein isothiocyanate dextran-loaded lysosomes and correlated with the ATP-dependent efflux of lysosomal cystine. The lysosomal ATPase was distinct from(More)
The alpha(3)(betaM(222)S/Y(345)W)(3)gamma double-mutant subcomplex of the F(1)-ATPase from the thermophilic Bacillus PS3 (TF(1)), free of endogenous nucleotides, does not entrap inhibitory MgADP in a catalytic site during turnover. It hydrolyzes 100 nM-2 mM ATP with a K(m) of 31 microM and a k(cat) of 220 s(-)(1). Fluorescence titrations of the introduced(More)
Aminoguanidine, N,N'-diaminoguanidine, methylguanidine, and 1,1-dimethylguanidine were compared to NG-monomethyl-L-arginine (L-NMMA) for their ability to inhibit nitric oxide (NO) formation by cytokine-inducible and vascular constitutive isoforms of NO synthase. These comparisons were performed by assessing (1) cytokine-induced production of nitrite by(More)
A mutant alpha3beta3gamma complex of F1-ATPase from thermophilic Bacillus PS3 was generated in which noncatalytic nucleotide binding sites lost their ability to bind nucleotides. It hydrolyzed ATP at an initial rate with cooperative kinetics (Km(1), 4 microM; Km(2), 135 microM) similar to the wild-type complex. However, the initial rate decayed rapidly to(More)
NO is produced during cardiac allograft rejection by expression of inducible NO synthase (iNOS) in the rejecting heart. Recent evidence indicates that NO modulates vascular permeability under both physiological and pathophysiological conditions. The present study explored the effects of early acute cardiac allograft rejection, and specifically the effects(More)
It has been reported that shifts in the fluorescence emission spectrum of the introduced tryptophans in the betaF155W mutant of Escherichia coli F(1) (bovine heart mitochondria F(1) residue number) can quantitatively distinguish between the number of catalytic sites occupied with ADP and ATP during steady-state ATP hydrolysis (Weber, J., Bowman, C., and(More)