Differential stimulation of the GTPase activity of G-proteins by polylysine
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1992Metadata
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Antonelli, Marcelo
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Differential stimulation of the GTPase activity of G-proteins by polylysine
Abstract
Polylysine, polyornithine and, to a lesser extent, polyarginine were found to stimulate the GTPase activity of the purified recombinant α subunit of the human Gi-3 transducing protein αi-3. Optimal stimulation of 4- to 5-fold was obtained with polysine concentrations between 1 and 20 μM, higher concentrations being inhibitory. Polylysine at similar concentrations stimulated by 50% the GTPase of transducin (gt), the vision transducing protein, but had only a very slight effect on the GTPase of the p21 product of the H-ras protooncogene. The stimulation of the αi-3 GTPase caused by polylysine was due to a reduction of the apparent Km for GTP from 3.8 to 1.3 μM. The stimulation by polylysine was observed at free Mg2+ concentrations below 1 μM. These results indicate that polylysine acts in a fashion similar to mastoparan and substance P in mimicking the action of an agonist-bound receptor on G-proteins. © 1992.
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URI: https://repositorio.uchile.cl/handle/2250/161083
DOI: 10.1016/0006-2952(92)90448-R
ISSN: 00062952
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Biochemical Pharmacology, Volumen 44, Issue 3, 2018, Pages 547-551
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