Protocol to measure endogenous GlcNAc-1-phosphotransferase activity in SK-MEL-30 cells

Summary: GlcNAc-1-phosphotransferase (GNPT) is the key enzyme for tagging lysosomal hydrolases with the mannose 6-phosphate moiety for delivery to the lysosome. Here, we present the assay for measuring endogenous GNPT activity in SK-MEL-30 cells. We provide details for preparing the [3H]UDP-GlcNAc d...

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Main Authors: Balraj Doray, Danielle Henn, Xi Yang, Ming Li, Patricia Dickson
Format: Article
Language:English
Published: Elsevier 2025-09-01
Series:STAR Protocols
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Online Access:http://www.sciencedirect.com/science/article/pii/S2666166725003417
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author Balraj Doray
Danielle Henn
Xi Yang
Ming Li
Patricia Dickson
author_facet Balraj Doray
Danielle Henn
Xi Yang
Ming Li
Patricia Dickson
author_sort Balraj Doray
collection DOAJ
description Summary: GlcNAc-1-phosphotransferase (GNPT) is the key enzyme for tagging lysosomal hydrolases with the mannose 6-phosphate moiety for delivery to the lysosome. Here, we present the assay for measuring endogenous GNPT activity in SK-MEL-30 cells. We provide details for preparing the [3H]UDP-GlcNAc donor substrate and conditions for the enzymatic transfer of [3H]GlcNAc-1-P to the methyl α-D-mannopyranoside acceptor (α-MM). We then describe the chromatography steps to specifically separate the [3H]GlcNAc-1-P-αMM GNPT reaction product from unreacted [3H]UDP-GlcNAc that is bound to the quaternary aminoethyl (QAE) Sephadex A-25 matrix.For complete details on the use and execution of this protocol, please refer to Doray et al.1 and Yang et al.2 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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spelling doaj-art-69c528ae8a8a4341938b2c5ffb87c7af2025-08-20T03:33:38ZengElsevierSTAR Protocols2666-16672025-09-016310393510.1016/j.xpro.2025.103935Protocol to measure endogenous GlcNAc-1-phosphotransferase activity in SK-MEL-30 cellsBalraj Doray0Danielle Henn1Xi Yang2Ming Li3Patricia Dickson4Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA; Corresponding authorDepartment of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USADepartment of Biological Sciences, University of Denver, Denver, CO 80208, USADepartment of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USADepartment of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA; Corresponding authorSummary: GlcNAc-1-phosphotransferase (GNPT) is the key enzyme for tagging lysosomal hydrolases with the mannose 6-phosphate moiety for delivery to the lysosome. Here, we present the assay for measuring endogenous GNPT activity in SK-MEL-30 cells. We provide details for preparing the [3H]UDP-GlcNAc donor substrate and conditions for the enzymatic transfer of [3H]GlcNAc-1-P to the methyl α-D-mannopyranoside acceptor (α-MM). We then describe the chromatography steps to specifically separate the [3H]GlcNAc-1-P-αMM GNPT reaction product from unreacted [3H]UDP-GlcNAc that is bound to the quaternary aminoethyl (QAE) Sephadex A-25 matrix.For complete details on the use and execution of this protocol, please refer to Doray et al.1 and Yang et al.2 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.http://www.sciencedirect.com/science/article/pii/S2666166725003417Cell BiologyMolecular BiologyProtein Biochemistry
spellingShingle Balraj Doray
Danielle Henn
Xi Yang
Ming Li
Patricia Dickson
Protocol to measure endogenous GlcNAc-1-phosphotransferase activity in SK-MEL-30 cells
STAR Protocols
Cell Biology
Molecular Biology
Protein Biochemistry
title Protocol to measure endogenous GlcNAc-1-phosphotransferase activity in SK-MEL-30 cells
title_full Protocol to measure endogenous GlcNAc-1-phosphotransferase activity in SK-MEL-30 cells
title_fullStr Protocol to measure endogenous GlcNAc-1-phosphotransferase activity in SK-MEL-30 cells
title_full_unstemmed Protocol to measure endogenous GlcNAc-1-phosphotransferase activity in SK-MEL-30 cells
title_short Protocol to measure endogenous GlcNAc-1-phosphotransferase activity in SK-MEL-30 cells
title_sort protocol to measure endogenous glcnac 1 phosphotransferase activity in sk mel 30 cells
topic Cell Biology
Molecular Biology
Protein Biochemistry
url http://www.sciencedirect.com/science/article/pii/S2666166725003417
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AT mingli protocoltomeasureendogenousglcnac1phosphotransferaseactivityinskmel30cells
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