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Unformatted text preview: protein kinases and phosphatases. a. Human genome codes for > 500 kinases; >100 phosphatases. b. Approx. 50% of all proteins in a cell are potential substrates for phosphorylation. 2. GTP-binding proteins (G-proteins) function as on / off switches. a. Nucleotide binding causes conformational change in G-protein (GTP = on; GDP = off). b. G-proteins have weak intrinsic GTPase activity; this can be stimulated by interaction with GTPase Activating Proteins (GAPs). c. G-protein regulators i. GAPs (GTPase activating proteins) shorten duration of "on" response by speeding up GTPase activity. ii. GEFs (guanine nucleotide exchange proteins): enhance release of GDP; facilitates binding of available GTP = "on". iii. GNDIs (guanine nucleotide dissociation inhibitors): inhibit release of bond GDP, thus enhancing the "off signal. Demo...
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This note was uploaded on 05/24/2010 for the course BIS 104 taught by Professor Scholey during the Spring '08 term at UC Davis.
- Spring '08