Current Search: Cellular Structures (x)
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Title
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Retention efficiencies of the coral reef sponges Aplysina lacunosa, Callyspongia vaginalis and Niphates digitalis determined by Coulter counter and plate culture analysis.
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Creator
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Duckworth, Alan R., Bruck, W. M., Janda, Kathleen E., Pitts, Tara P., McCarthy, Peter J.
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Date Issued
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2006
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PURL
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http://purl.flvc.org/FCLA/DT/2796072
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Subject Headings
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Sponges --Florida --Identification, Sponges --Congresses, Microorganisms, Deep-sea biology, Cellular Structures
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Format
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Document (PDF)
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Title
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Purification and characterization of two members of the protein tyrosine phosphatase family: dual specificity phosphatase PVP and low molecular weight phosphatase WZB.
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Creator
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Livingston, Paula A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
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Abstract/Description
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Two protein tyrosine phosphatases, dual specificity phosphatase PVP and low molecular weight phosphatase WZB were purified and characterized. PVP was expressed as inclusion bodies and a suitable purification and refolding method was devised. Enzyme kinetics revealed that p-nitrophenylphosphate and (Sb(B-naphthyl phosphate were substrates with KM of 4.0mM and 8.1mM respectively. PVP showed no reactivity towards phosphoserine. Kinetic characterization of WZB showed that only...
Show moreTwo protein tyrosine phosphatases, dual specificity phosphatase PVP and low molecular weight phosphatase WZB were purified and characterized. PVP was expressed as inclusion bodies and a suitable purification and refolding method was devised. Enzyme kinetics revealed that p-nitrophenylphosphate and (Sb(B-naphthyl phosphate were substrates with KM of 4.0mM and 8.1mM respectively. PVP showed no reactivity towards phosphoserine. Kinetic characterization of WZB showed that only pnitrophenylphosphate was a substrate with no affinity for Ç-naphthyl phosphate and phosphoserine. Optimal conditions for activity with PNPP were found at a pH of 5 with a KM of 1.1mM, kcat of 35.4s-1 and kcat/KM of 32.2s-1mM-1. Inhibition studies showed that phosphate, fluoride, and molybdate were competitive inhibitors with Ki of 3.2mM, 71.7mM, and 50.4(So(BM respectively and hydrogen peroxide abolished activity. Active site mutants of WZB Cys9Ser and Asp115Asn showed no activity.
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Date Issued
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2009
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PURL
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http://purl.flvc.org/FAU/332911
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Subject Headings
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Protein-tyrosine phosphatase, Cellular signal transduction, Cell cycle, Regulation, Membrane proteins, Structure-activity relationships, Protein kinases
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Format
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Document (PDF)
