Some properties of the adenyl cyclase activity in the maturing testis of Oncorhynchus tshawytscha (chinook salmon) were characterized. The enzymic reaction was linear at 30° and at 15° for at least 60 min. The divalent cation requirement of the salmon testis enzyme was reexamined (33). The optimal concentration of Mg was about 10 mM and of Mn2+ was 5 mM; Mn2+ concentrations above 15 mM caused a marked decrease in enzyme activity. A higher maximal activity was achieved in the presence of Mn2+ than in the presence of Mg2+. Stimulation of the enzyme with the optimal concentration of F-, 12 mM, resulted in a 7-fold increase in the reaction rate over the basal activity.
In efforts to solubilize the enzyme, it was found that Lubrol PX and Triton X-100 destroyed enzymic activity but Nonidet P40 and Tween 80 did not.
The adenyl cyclase activity in salmon testis homog-enates was stable for at least 6 hours at 0° to 4° but was very unstable at 24°; storage of the homogenate for 24 hours at either 0° to 4° or 24° resulted in a total loss of activity.
Differential centrifugation of salmon testis homog-enates which were prepared in isotonic medium revealed tnat all subcellular fractions contained some adenyl cyclase activity. About 55% of the activity sedimented at 600g while only 10% of the activity was recovered in the 105,000g supernatant. The 6300g sediment had a very high specific activity compared with the specific activity
of the other fractions.
The ATP analogue, adenylyl imidodipho3phate (AMP-PNP), tritium labeled in adenosine, was synthesized from tri-butylammonium imidodiphosphate and adenosine-5’ phosphor-imidazolate. Salmon testis adenyl cyclase catalyzed the conversion of AMP-PNP to cyclic AMP. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/18684 |
| Date | January 1974 |
| Creators | Bendix, Marie Elaine |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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