..................................................
Figure 1. The structure of the galactose and phosphate binding sites from L. lactis galactokinase [14]. The protein was crystallised in the presence of both galactose and inorganic phosphate (both shown with yellow bonds). The following colour scheme has been used for the atoms: Carbon = black, Oxygen = red, Nitrogen = blue, Phosphate = pink. Distances of less than 0.32 nm are shown as dashed lines. Figure courtesy of Hazel Holden (University of Wisconsin).
..................................................
Figure 2. The structures of the sugars used in this investigation.
..................................................
Figure 3. 2-deoxy-D-galactose (2dG) is a substrate for human galactokinase. Steady state kinetic analysis was carried out as described in Materials and Methods. Each kcat,app value is derived, using non-linear curve-fitting [25], from a set of rates data at a single sub-saturating substrate concentration. Error bars represent the standard error in kcat,app as derived by from the fitting process. The lines are non-linear curve fits of the kcat,app data to the equation kcat,app = kcat[substrate]/(Km + [substrate]). The following parameters were derived from this fitting: kcat = 4.8 ± 0.3 s-1; Km,ATP = 59 ± 9 μM; Km,2dG = 1100 ± 110 μM; kcat/Km,ATP = (8.1 ± 0.8) × 104 l.mol-1.s-1; kcat/Km,2dG = 4200 ± 270 l.mol-1.s-1.
..................................................
Figure 4. Kinetic analysis of the soluble mutants, E43A and E43G. Error bars represent the standard error as derived from the non-linear curve fitting (see materials and methods). The kinetic parameters derived from these curve fits are detailed in table 1.
..................................................
Source: BMC Biochemistry 2003, 4:16
Answers to all your Biology Questions
