Immunogen sequence: TTMGYQSGEL IGKELGEVPI NEKKADLLDT INSCIRIGKE WQGIYYAKKK NGDNIQQNVK IIPVIGQGGK IRHYVSIIRV CNGNNKAEKI SECVQSDTHT DNQTGKHKDR RKGSLDVKAV ASRATEVSSQ RRHSS. Phosphodiesterases (PDEs) regulate the intracellular levels of cAMP and cGMP. These