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L S Bradham

Publications and source records attributed to L S Bradham.

7 recordsLinked to original sources
PubMed1983

Separation of the catalytic and stimulatory regulatory subunits of rat brain adenylate cyclase.

The catalytic subunit of rat brain adenylate cyclase was separated from its stimulatory subunit with loss of activation by 5'-guanylylimidodiphosphate. With respect to other properties, the resolved catalytic subunit was similar to the native enzyme. Nucleotide activation was restored after reconstitution with the isolated regulatory subunit. A key step in resolution was preliminary exposure of isolated membranes to increased ionic strength. After solubilization with nonionic detergent solution, the subunits were separated by gel filtration. The apparent molecular size of the catalytic subunit was unchanged by salt treatment, whereas the Stokes' radius of the regulatory subunit decreased from 72 A to 48 A.

Adenylyl Cyclases↗
PubMed1977

Fluoride activation of rat brain adenylate cyclase: the requirement for a protein co-factor.

Activation of particulate adenylate cyclase and detergent-soluble (lubrol PX) adenylate cyclase occurred when the enzyme was preincubated at 37 degrees in the presence of 5 mM NaF and 5mM MgSO4. Under these conditions the specific activity of the enzyme increased more than twofold in 8 to 12 min. Activation also occurred in the presence of 5 mM NaF alone, but the rate of activation was slower. Under these conditions, activation was inhibited by 1mM EDTA, but this inhibition was prevented byMg++. No activation was observed at 0 degrees or in the absence of F. After repeated extraction with detergent, particulate adenylate cyclase was not stimulated by mM NaF, and activation by preincubation with Mg++ and F- was significantly reduced. Activation was restored by recombination of this particulate fraction with the initial detergent extract. This activating effect appeared to be mediated by one or more proteins present in the detergent extract.

Adenylyl Cyclases↗