Phospholipase A2 in salivary glands isolated from tobacco hornworms, Manduca sexta

Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology
Hasan Tunaz, David Stanley

Abstract

We describe a phospholipase A2 (PLA2) associated with the salivary glands of tobacco hornworms, Manduca sexta. This enzyme is able to hydrolyze arachidonic acid from the sn-2 position of PLs. Addition of the calcium chelator, EGTA, or calcium, to the Tris reaction buffer impaired the PLA2 activity, from which we infer the enzyme requires very low concentrations of calcium or perhaps other ions for optimal activity. PLA2 activity was sensitive to protein concentration (highest activity at 25 microg protein per microl), reaction time (optimal at 30 min), buffer pH (optimal at pH 8-10), and reaction temperature (optimal range 18-38 degrees C). The salivary gland PLA2 was sensitive to the site-specific inhibitor, oleyloxyethylphosphorylcholine and stable to freezing at -80 degrees C, but not -20 degrees C. The biological significance of this enzyme may relate to hydrolysis of fatty acid moieties from dietary PLs for absorption by midgut epithelia. This salivary gland enzyme may also be responsible for killing food-borne bacteria.

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Citations

Dec 2, 2011·Journal of Parasitology Research·Mário A C Silva-NetoGeorgia C Atella
Sep 7, 2012·Archives of Insect Biochemistry and Physiology·Mohammad Saadati BezdiSetsuko Komatsu
Jul 29, 2006·Comparative Biochemistry and Physiology. Toxicology & Pharmacology : CBP·S NagarajuK Kemparaju
Jul 11, 2006·Biochimica Et Biophysica Acta·David Stanley
Oct 16, 2012·Journal of Insect Physiology·Bridget DeLayWilliam Lamp
Feb 23, 2019·Frontiers in Physiology·David Stanley, Yonggyun Kim
Nov 24, 2020·BMC Genomics·Vinod Kumar PrajapatiJyothilakshmi Vadassery

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