Tyrosine, Cysteine, and S-Adenosyl Methionine Stimulate In Vitro [FeFe] Hydrogenase Activation
Figure 4
Experimental design for elucidation of amino acids enhancing in vitro hydrogenase activation.
Amino acid mixtures (aa Mix) were added to hydrogenase maturation reactions to a final concentration of 2 mM for each amino acid. The maturation reaction mixtures contained 60% vol·vol−1 maturase extract reconstituted with Fe+2 and S−2 for 60 min, and then pre-treated with SAM and one of the 32 aa mixtures for 60 min prior to apoHydA1 addition (4.1 µM). HydA1 specific activities were determined at t = 10 min (Response R1) and t = 9 hr (Response R2), and values are expressed as pmol H2 consumed·min−1·ng−1 for n = 1 experiment. ANOVA was performed for both responses to determine F-statistics and p-values. The 20 individual amino acid effects were selected for analysis by the regression models. Each F-statistic equals the ratio of mean squares for that particular amino acid (1 degree of freedom) to that of the residuals (11 degrees of freedom). P-values represent the statistical significance of the F-statistics.