High impact information on ENTPD4

• Our data suggest that the presence or absence of the 8-amino acid motif VSFASSQQ provoke differences in substrate specificity and divalent cation dependence of hLALP70/hLALP70v [1].
• By fluorescence in situ hybridization analysis, the hLALP70 gene was mapped to the human chromosome 8p21.1-p21 [1].
• In contrast, hLALP70 enzymatic activity were unsaturated up to 10 mm Ca(2+), while Mg(2+) showed a saturation at already 1 mm concentration with 2-3-fold lower enzymatic activity as observed with Ca(2+) [1].
• This is the first identification of a mammalian Golgi luminal UDPase gene [2].
• UDP hydrolysis was increased in the presence of Triton X-100 or alamethicin, an ionophore that facilitates movement of UDP across the membrane, suggesting that the active site of this UDPase is on the luminal side of the Golgi apparatus [2].

Biological context of ENTPD4

• Using antibodies against autophagic vacuole membrane proteins we identified a human cDNA with an open reading frame of 1848 bp, encoding a protein of 70 kDa, which we named lysosomal apyrase-like protein of 70 kDa (LALP70) [3].

Anatomical context of ENTPD4

• A human intracellular apyrase-like protein, LALP70, localizes to lysosomal/autophagic vacuoles [3].
• GalAT and latent UDPase activities were separated from the majority (80%) of callose synthase activity, a marker for the plasma membrane, suggesting that little or no GalAT is present in the plasma membrane [4].
• GalAT activity in homogenates from pea (Pisum sativum L. var. Alaska) stem internodes co-localized in linear and discontinuous sucrose gradients with latent UDPase activity, an enzyme marker specific for Golgi membranes [4].
• One group of enzymes, including nucleoside diphosphatases (IDPase, UDPase, GDPase, ADPase), carbamoyl phosphatase, alkaline phosphatase, and BAXD oxidase was localized mainly in the rough endoplasmic reticulum, nuclear envelope, and convex side of the Golgi apparatus [5].

Associations of ENTPD4 with chemical compounds

• 5. Detergent treatment with 0.1% sodium deoxycholate allows the partial solubilization of the glucosyltransferase and UDPase [6].

Other interactions of ENTPD4

• Of several nucleoside diphosphatase activities, UDPase activity is most enhanced by the freeze-thaw and sucrose-density-gradient-fractionation procedures [6].

Analytical, diagnostic and therapeutic context of ENTPD4

• Sequence analysis revealed that LALP70 belongs to the apyrase or GDA1/CD39 family and is almost identical to a human uridine diphosphatase, with the exception of nine extra amino acids in LALP70 [3].
• In this report we used a thin layer chromatography approach to study separately the UTPase and UDPase activity of the two LALP-enzymes [7].

References