pyy and neuropeptide y ( npy ) bound with high affinity to crude membrane preparations from the hippocampus , but their c-terminal fragments bound with 30- to 450-fold lower affinity guanine nucleotides , especially the nonhydrolyzable gtp analog gtp gammas inhibited the binding of [ 125i ] pyy , but other transmitters , hormones , and central nervous system-acting drugs did not , except for gangliosides at high concentrations .
C0018328
guanine
C0018353
gtp