ENTPD1 original evidence and access guide
The review distinguishes native human enzyme preparations, human recombinant constructs, other species and the six source-described natural products. No new publication quotations are added. “Original read” below means the listed operative text and captions were inspected; it does not mean figure pixels were independently reanalyzed. Normal publication-cache availability flags are distinct from this actual reviewer access.
Direct enzyme evidence
- PMID:8529670, original DOI, publisher PDF. Read the nine-page original, especially p67 Enzymic assays, p70 purification/alkaline-phosphatase exclusion and Fig2, and p71 Fig4/Table3. Native human placental enzyme releases phosphate from ATP, GTP, ITP, CTP, ADP, GDP and IDP. Table3 does not test CDP, UDP or UTP. The preparation is not isoform resolved.
- PMID:8626624, correct original DOI, publisher original. Read Experimental Procedures (Assay of Apyrase Activity and RT-PCR), initial Results on human LG2 cells, part of Demonstration of CD39 as an Ecto-apyrase, and Discussion. These establish ATP hydrolysis and human CD39 expressed in COS-7 cells. The full alternative-substrate table was not recovered. The normal UniProt reference block and external Europe PMC metadata contain an incorrect DOI ending10391; the PMID/title remain correct.
- PMID:8955160, original DOI, PubMed. Identifier and abstract verified; operative full text remains unavailable. It reports human endothelial CD39 cDNA/COS-7 activity and platelet suppression. The integrated decisions use independent inspected originals for supported enzyme/localization/antiplatelet claims without claiming this paper was fully read.
- PMID:8996251, original DOI, official full original. Read Methods sec8 Characterization of vascular ATPDase, Results sec19/Fig1 platelet inhibition, sec20/Fig2 biochemical identification, and sec22/Fig5 surface CD39. Native human and pig endothelial cells are distinguished from porcine ADP TLC and the separate rat renal experiment. The nonhydrolyzable ADP-beta-S control connects platelet suppression to nucleotide hydrolysis. Early activity loss occurs without a corresponding loss of surface CD39. Adenosine formation downstream requires separate 5-prime-nucleotidase activity.
Human localization and interaction
- PMID:10636909, correct original DOI, author-uploaded original. Read Experimental Procedures (Cell Culture, ATPDase Assays, Enzyme Cytochemistry and Immunostaining) and localization Results/Figures4–5. Native human HUVECs in Figure5 and human CD39 expressed in COS-7 in Figure4 support plasma-membrane/caveolar association. Synthetic N-terminal deletion does not isolate palmitoylation alone or identify a natural alternative product.
- PMID:16478441, original DOI, official full original. Read Experimental and Results, Figures1–4 captions and Table1 summary/legend. Human bait, reciprocal recombinant co-IP and endogenous human B-cell complexes support RanBPM association; Figure3 measures ATP/ADP hydrolysis modulation. Mouse splenic expression is separate. The adapter is RanBPM; CD39 is not assigned adapter activity.
Placental products
- PMID:9846014, original DOI. Identifier/abstract verified; full operative original unavailable. The native MK33-immunopurified placental product is not assigned to every isoform. A title describing a difference from CD39 does not establish wrong-gene attribution.
- PMID:10405171, original DOI, publisher original. Read Methods2.1–2.6 and Results/Discussion3. Human placental cDNAs AJ133133/AJ133134 correspond to reported517/306-residue products. Sequence/transcript evidence and predicted topology do not establish recombinant enzyme-II activity or uniform substrate scope.
Localization datasets with remaining gaps
- PMID:7930580, original DOI, publisher original. Abstract/identifier verified; full article unavailable. Human cloning/topology is supported, but the earlier antibody-induced homotypic B-cell adhesion experiment was not recovered. That annotation remains unresolved; plasma membrane is independently established above.
- PMID:19946888, original DOI, listed Supplementary Table1. Abstract and table filename verified; operative article and ENTPD1-specific YTS membrane-proteome entry unavailable. Plasma-membrane refinement rests on independent native human localization, not on assumed purity of this preparation.
- PMID:20458337, original DOI, author-uploaded original. Read Results Identification of exosomal proteins/Fig1 and Methods Cell culture and exosome isolation, Isolation of MHC II-associated proteins, Mass spectrometry and MS data analysis. Human RN B-cell exosome preparation and peptide/replication criteria are clear. The ENTPD1 entry in SupplementaryTable1 remains inaccessible. MainTable1 concerns separate MHC-II co-IP; it does not establish an ENTPD1 interaction or exosome-biogenesis role.
Donor evidence and source interpretation
- PMID:11929769, original DOI, author-uploaded original. Read Immunohistochemistry and Triple staining/confocal Methods, localization Results and Figures3–5 captions. Cardiac localization is mouse tissue; expression constructs are mouse NTPDase1 and rat NTPDase2, with corresponding mouse/rat antisera recognition. NTPDase1 is predominantly endothelial; NTPDase2 marks adventitial/pericyte populations associated with basal lamina. These experiments do not establish NTPDase1 within basement-membrane matrix. The GO definition concerns matrix, not a contacting cell membrane. This is a bounded source-compartment interpretation issue, not wrong orthology or a universal negative.
- PMID:17502665, original DOI, official original. Read operative Results/Fig3 and Methodssec12–13 (intact-cell ATP phosphate release and radiolabeled ADP TLC), with surface-expression and knockout context. Mouse T-cell CD39 surface catalysis and ADP degradation support the donor assertions. CD73 supplies downstream AMP conversion; unpublished human/primate observations are not treated as human replication.
- PMID:22100451, original DOI, publisher original. Identifier, original abstract, Introduction and short section snippets verified. The operative UDP/UTP substrate methods/results were not recovered. Engineered rat soluble ectodomains and membrane-interaction-loop deletion are not human natural isoforms. The narrow rat/Rhea UDP evidence chain remains unresolved; the distinct PAINT ancestral assertion is evaluated through its actual node.
Database and product provenance
PANTHER family PTHR11782 places human P49961 at PTN002483056 in ENTPD1 subfamilySF32. Six imported IBA assertions match actual IBD nodes: PTN000207579 for GDP/UDP/NTP activities, PTN000925965 for plasma membrane, and PTN000746626 for NDP/NTP catabolism. Target descent and the exact donor sets were checked against the pinned IBD; no matching NOT record occurs on the target path. A target self-donor is valid experimental grounding.
Reactome NTP event8850846 and NDP event8850854 were traced through catalysts8850850/8850852 and complexes8850845/8850847 to human P49961 protein913566. Calcium/magnesium is a set of alternatives. Rhea aggregate NTP-to-NMP chemistry releases two inorganic phosphates; component reactions and substrate-specific evidence are distinguished. InterPro IPR000407 supports the broad family hydrolase mapping. Current inaccessible or unmatched ARBA rules do not override independent experiments.
The six imported products remain P49961-1(510),-2(517),-3(306),-4(372),-5(402),-6(522). All reconstruct exactly from UniProt P49961 alternative sequences and independently downloaded FASTA records. Coordinate projection establishes sequence differences, not activity, topology in a particular cell or equivalence to artificial constructs. The short placental product lacks the unchanged canonical C-terminal membrane-spanning segment; products4/5 lack the unchanged canonical N-terminal segment. Retaining one catalytic residue does not establish catalytic competence.
Core synthesis and reproducible products
One apyrase unit represents successive extracellular ATP/ADP hydrolysis with phosphate release, class-level nucleotide catabolism and the demonstrated contribution to negative regulation of platelet aggregation. The external side of the plasma membrane is the specific core location supported by the human surface evidence. The independently read originals are PMID:8529670 (printed pp. 67, 70–71; Table 3), PMID:8996251 (Methods, Fig. 1 and human surface Fig. 5), and PMID:10636909 (Methods, Fig. 4 and Fig. 5 Results). Native placental enzyme was not isoform resolved; endothelial human and porcine experiments remain distinguished. A separate CD73 reaction produces adenosine. The product-analysis bundle supplies exact replay inputs and coordinate projections for all six source-described human products; these projections do not establish functional equivalence.
Follow-up evidence boundaries
PMID:17502665(https://doi.org/10.1084/jem.20062512), official PMC Results sections3–5/Figures3–5 and Methods12–15, connects mouse CD39-dependent nucleotide degradation to CD73-mediated adenosine generation, A2A-dependent responses, proliferation and graft suppression. This supports the immune-regulatory context while leaving AMP hydrolysis with CD73. Human/primate observations in that paper remain unpublished.
PMID:16478441(https://doi.org/10.1042/BJ20051568), Results and Figures1–3, supports human CD39–RanBPM association and identifies CD39 as the enzyme whose ATP/ADP hydrolysis is reduced by RanBPM. It does not establish CD39 as an adapter or an enzyme regulator. The review retains the supported association as non-core under the campaign instructions.
The CDP/UDP questions identify measurements missing from the inspected human substrate panel and the partially accessible rat original; they do not erase the accepted PAINT UDP assertion or claim that the entire literature lacks those measurements.