Histaminantagonistische Wirkungen von Adrenochrom-Monosemicarbazon

Diphosphopyridine nucleotide dependent isocitrate dehydrogenase from pig heart. Characterization of active substrate and modes of regulation

“…It is evident that the of the DPN-dependent isocitrate dehydrogenase reaction does change with the concentration of hydrogen ion. By assuming the simplest model, which postulates that the Hmax depends on the presence of the basic form of one ionizable group in the enzyme-substrate complex, it is possible to assign a value to the pK of this group from the equation (Alberty, 1956) V™x°1 + [(H+)/A-"J figure 5: Determination of the pK of the enzyme-substrate complex. The data obtained between pH 6.0 and 7.0 in Figure 1 are plotted here in accordance with the following equation: 1/Fmai0 = {1/Fmaxi + [(H+)/( FmMiXA'aes)]}.…”

Isolation and properties of malic dehydrogenase from ox-heart mitochondria

“…3B). The Km value determined by extrapolation was 1X8 x 10-5M at pH 6*7 and by substituting in the rate-law equation for a bimolecular enzyme reaction (Alberty, 1956) a Km value of 2B6 x 10M was obtained. Determination ofthe Km for DPNH with a constant oxaloacetate concentration of 10-I'M gave 2x 105matpH607.…”

“…The simplest explanation of the anomalies found in the Lineweaver-Burk plots is that the enzyme has two sites for the substrate, one of which is catalytically active, the other forming an enzyme-substrate complex which may inhibit or activate the enzyme depending on the substrate (Alberty, 1956). Neglecting the fact that a ternary complex between enzyme, substrate and coenzyme is probably formed, we may write k, k3 E + S = ES -+ E + P, Following the convention of Alberty (1956), SE represents a substrate-enzyme complex which does not break down to yield products.…”

On the Structure and Function of Reduced Nicotinamide Adenine Dinucleotide Phosphate‐Cytochrome f Reductase of Spinach Chloroplasts

“…This indicates, according to the equations derived by Alberty 1371, a two-step reaction, in which the enzyme is first reduced by the electron donor, which is oxidized, and the reduced enzyme is subsequently oxidized by the electron acceptor. [37], the formation of a ternary complex, NADPH-enzyme-cyt. f. This finding has now been confirmed, and is illustrated in Fig.4.…”