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HERBERT ZIMMERMANN Y COLS. AN. R. ACAD. NAC. FARM.

TABLE 1. Ecto-nucleotidases and other enzymes metabolizing extracellular
nucleotides

Family Surface-located Substrates Final product Inhibitors
forms

Ecto-nucleoside NTPDase1, NTP, NDP NMP ARL 67156, 8-BuS-
triphosphate NTPDase2, ATP,
diphos- NTPdase3, polyoxometalates,
phohydrolases NTPDase8 P2 receptor
antagonists

Ecto-nucleotide NPP1, NPP3, NTP (NDP) NMP + PPi, (Pi) P2 receptor
pyrophosphatase/ NPP2, secreted NMP + Npn-1 antagonists,
phospho- dinucleoside heparin, heparan
diesterases polyphosphates sulphates

NAD+ AMP +
nicotinamide
mononucleotide

UDP-glucose UMP + Gluose-6-
phosphate

Alkaline Kidney/bone/liver NTP, NDP, Nucleoside Levamisole, L-
phosphatases [= tissue non- NMP homoraginine
specific form,
TNAP],

Placental, L-phenylalanine
Intestinal, Germ-
cell

Ecto-5’- Ecto-5’- NMP Nucleoside AOPCP
nucleotidase nucleotidase

Adenylate kinase AK1-6, not ADP or AMP + AMP + ATP or Ap5A
identified
ATP ADP

NAD+ CD38, CD157 NAD+ ADP-ribose and NAD+ analogues
glycohydrolases nicotinamide,
(NADases) (cyclic ADP-
ribose)

Mono(ADP- ART1-ART5 NAD+ ADP-ribosylated
ribosyl) ART2 NAD+ protein
transferases
ADP-ribose and
nicotinamide

Nucleoside nm23-M1-6, not N1TP, N2DP N1DP, N2TP
diphosphate identified
kinase

ATP-synthases Ecto-F1Fo ADP ATP Oligomycin
ATPsynthase/
F1 ATPase

Ap5A, P1P5-di (adenosine-5') pentaphosphate; ARL 67156, 6-N,N-diethyl-D-ß,? -dibromomethylene ATP;
BuS-ATP, 8-thiobutyladenosine 5’-triphosphate; AOPCP, a,ß-methylene adenosine 5’-diphosphate; both
ATP synthesis and ATP-hydrolysis has been reported for ecto-F1Fo ATPase. The subtype of surface-located

adenylate kinase and nucleoside diphosphate kinase has not been identified.

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