TY  - JOUR
A1  - Failer, Bernd Uwe
A1  - Braun, Norbert
A1  - Zimmermann, Herbert
T1  - Cloning, expression, and functional characterization of a Ca2+-dependent endoplasmic reticulum nucleoside diphosphatase
T2  - Journal of biological chemistry
N2  - We have isolated and characterized the cDNA encoding a Ca(2+)-dependent nucleoside diphosphatase (EC ) related to two secreted ATP- and ADP-hydrolyzing apyrases of the bloodsucking insects, Cimex lectularius and Phlebotomus papatasi. The rat brain-derived cDNA has an open reading frame of 1209 bp encoding a protein of 403 amino acids and a calculated molecular mass of 45.7 kDa. The mRNA was expressed in all tissues investigated, revealing two major transcripts with varying preponderance. The immunohistochemical analysis of the Myc-His-tagged enzyme expressed in Chinese hamster ovary cells revealed its association with the endoplasmic reticulum and also with pre-Golgi intermediates. Ca(2+)-dependent nucleoside diphosphatase is a membrane protein with its catalytic site facing the organelle lumen. It hydrolyzes nucleoside 5'-diphosphates in the order UDP >GDP = IDP >>>CDP but not ADP. Nucleoside 5'-triphosphates were hydrolyzed to a minor extent, and no hydrolysis of nucleoside 5'-monophosphates was observed. The enzyme was strongly activated by Ca(2+), insensitive to Mg(2+), and had a K(m) for UDP of 216 microm. Ca(2+)-dependent nucleoside diphosphatase may support glycosylation reactions related to quality control in the endoplasmic reticulum.
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/76035
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-760354
SN  - 0021-9258
VL  - 277.2002
IS  - 40
SP  - 36978
EP  - 36986
PB  - American Society for Biochemistry and Molecular Biology Publications
CY  - Bethesda, Md
ER  -