Figure 5.

(A) Comparison of inhibitory effects of gallate derivatives on CT-catalyzed ADP-ribosylation. Assays contained CT, agmatine, and [¹⁴C]NAD, as described in Materials and Methods without or with gallic acid or gallate derivatives (2 μg/ml). Values represent means ± SD for three determinations. *, P < 0.05; **, P < 0.01, by unpaired t test. N.S., not significant. (B) Effect of gallate derivatives on CT-catalyzed ADP-ribosylation of agmatine. ADP-ribosyltransferase activity of CT was determined in the agmatine assay with [¹⁴C]NAD as an ADP-ribose donor. CT was incubated with agmatine and [¹⁴C]NAD in the presence or absence of gallic acid (□), RG-tannin (○), 4G-G (■), 6G-Gol (⧫), 7G-M (▴), and 9G-T (●). Values represent means ± SD for three determinations.