Temperature and thiol-induced desensitization of a Ca2+-sensitive cyclic-3',5'-nucleotide phosphodiesterase from sheep lung
Radhakrishnan, T.S.; Savithri, H.S.; Rao, N.A.; Venkitasubramanian, T.A.
Biochemistry International 17(5): 927-933
1988
ISSN/ISBN: 0158-5231 PMID: 3254167 Document Number: 316336
Ca2+-sensitivity of sheep lung cyclic-3',5'-nucleotide phosphodiesterase is provided by endogenous tightly bound calmodulin. The calcium sensitivity of a highly purified enzyme was desensitized by increasing the assay temperature. It could also be desensitized to Ca2+-activation by thiols such as dithiothreitol. The thiol-induced desensitization could be partially reversed by dialysis and almost completely reversed by dilution. The results presented in this paper indicate that thiols are possibly involved in the interaction of calmodulin with cyclic-3',5'-nucleotide phosphodiesterase. This is the first report on temperature and thiol-induced desensitization of Ca2+-sensitivity of a cyclic-3',5'-nucleotide phosphodiesterase.