Nonhydrolyzable GTP Analogs Many enzymes can hydrolyze GTP between the and y phosphates. The GTP analog B,y-imidoguanosine 5'-triphosphate Gpp(NH)p, shown below, cannot be hydrolyzed between the 8 and y phosphates. Predict the effect of microinjection of Gpp (NH)p into a myocyte on the cell's response to -adrenergic stimulation. H 0 I 0-1 -N-P-O-P-0-CH O 0 0 HN HN Gpp(NH)p H H H VH OH OH (8y-imidoguanosine 5'-triphosphate)