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Biosynthesis and secretion of acid phosphatase by Leishmania donovani promastigotes

Bates, P A and Dwyer, D M (1987) Biosynthesis and secretion of acid phosphatase by Leishmania donovani promastigotes. Molecular and Biochemical Parasitology, 26 (3). pp. 289-296. ISSN 0166-6851

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Abstract

Metabolic labeling and immunoprecipitation experiments demonstrated that soluble acid phosphatase (EC 3.1.3.2) was rapidly synthesized and released into culture medium by Leishmania donovani promastigotes. The kinetics of release indicated a constitutive secretory process (t 1/2 = 45 min). Moreover, acid phosphatase was the major secretory protein. The extracellular enzyme is composed of two heterodisperse bands of approximately 110 and 130 kDa in sodium dodecyl sulphate-polyacrylamide gels. It is synthesized as two intracellular precursors of 92.5 and 107 kDa which acquire the heterodisperse form characteristic of the mature extracellular enzyme during biosynthesis. Labeling in the presence of tunicamycin altered the electrophoretic mobility of the acid phosphatase, indicating the presence of several N-linked oligosaccharides on the mature enzyme. However, tunicamycin did not block secretion of the enzyme or its processing to the heterodisperse form. The biosynthetic effect of tunicamycin was mimicked by N-glycosidase F treatment of acid phosphatase immunoprecipitates. In contrast to tunicamycin, labeling in the presence of monensin inhibited processing of the phosphatase to its heterodisperse form. This indicates that Golgi processing, probably glycosylation, is responsible for the heterodispersity of the mature enzyme in sodium dodecyl sulphate-polyacrylamide gels. As with tunicamycin, monensin treatment did not prevent secretion of the acid phosphatase. These cumulative results demonstrate that release of this enzyme by L. donovani promastigotes occurs via a secretory pathway.

Item Type: Article
Journal or Publication Title: Molecular and Biochemical Parasitology
Uncontrolled Keywords: Leishmania donovani ; Acid phosphatase ; nzyme biosynthesis ; Secretion ; Glycosylation
Subjects: Q Science > QR Microbiology > QR355 Virology
Departments: Faculty of Health and Medicine > Biomedical & Life Sciences
ID Code: 56070
Deposited By: ep_importer_pure
Deposited On: 24 Jul 2012 10:24
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 20:46
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/56070

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