Cell surface adenosine deaminase: Much more than an ectoenzyme

Progress in Neurobiology

Volumn 52, Issue 4, 1997, Pages 283-294

  Franco, Rafael ^a   Casadó, Vicent ^a   Ciruela, Francisco ^a   Saura, Carles ^a   Mallol, Josefa ^a   Canela, Enric I ^a   Lluis, Carmen ^a  

^a UNIVERSITY OF BARCELONA   (Spain)

Author keywords

[No Author keywords available]

Indexed keywords

ADENOSINE DEAMINASE; MEMBRANE PROTEIN;

AMINO ACID SEQUENCE; ANIMAL CELL; CELL SURFACE; CELL TYPE; DEAMINATION; ENZYME ACTIVATION; ENZYME DEGRADATION; IMMUNOREACTIVITY; MOLECULAR INTERACTION; NERVOUS SYSTEM DEVELOPMENT; NONHUMAN; POSTSYNAPTIC MEMBRANE; PRIORITY JOURNAL; RECEPTOR DOWN REGULATION; REVIEW;

ADENOSINE DEAMINASE; ANIMALS; CELL MEMBRANE; MEMBRANE PROTEINS; MOLECULAR SEQUENCE DATA; SEQUENCE HOMOLOGY, AMINO ACID;

EID: 0030740773     PISSN: 03010082     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0301-0082(97)00013-0     Document Type: Review

References (104)

1. Adamson, R. H., Zaharevitz, D. W. and Johns, D. G. (1977) Enhancement of the biological activity of adenosine analogs by the adenosine deaminase inhibitor 2′-deoxycoformycin. Pharmacology 15, 84-89.
2. Adrian, G. S., Wiginton, D. A. and Hutton, J. J. (1984) Structure of adenosine deaminase mRNAs from normal and adensoine deaminase-deficient human cell lines. Mol. Cell. Biol. 4, 1712-1717.
3. 1 receptor-mediated inhibitory tonus: pre- and post-synaptic components. Neuroscience 57, 565-575.
4. Andy, R. J. and Kornfeld, R. (1982) The adenosine deaminase binding protein of human skin fibroblasts is located on the cell surface. J. Biol. Chem. 257, 7922-7925.
5. Aran, J. M., Colomer, D., Matutes, E., Vives-Corrons, J. L. and Franco, R. (1991) Presence of adenosine deaminase on the surface of mononuclear blood cells: immunochemical localization using light and electron microscopy. J. Histochem. Cytochem. 39, 1001-1008.
6. Ballarin, M., Fredholm, B. B., Ambrosio, S. and Mahy, N. (1991) Extracellular levels of adenosine and its metabolites in the striatum of awake rats: inhibition of uptake and metabolism. Acta Physiol. Scand. 142, 97-103.
7. Barnes, K., Kenny, J. and Turner, A. J. (1994) Localization of aminopeptidase N and dipeptidyl peptidase IV in pig striatum and in neuronal and glial cell cultures. Eur. J. Neurosci. 6, 531-537.
8. Bielat, K. and Tritsch, G. L. (1989) Ecto-enzyme activity of human erythrocyte adenosine deaminase. Mol. Cell. Biochem. 86, 135-142.
9. - SCID. Initial trial results after 4 years. Science 270, 475-480.
10. - immunodeficient patients. Science 270, 470-475.
11. Brandsch, M., Ganapathy, V. and Leibach, F. H. (1995) Role of dipeptidyl peptidase IV (DP IV) in intestinal and renal absorption of peptides. In: Dipeptidyl Peptidase IV (CD26) in Metabolism and the Immune Response, pp. 111-129. Ed. B. Fleischer. Springer: New York.
12. 1 adenosine receptor from pig brain: characterization and evidence of the role of the cell membrane on the coexistence of high- and low-affinity states. J. Neurosci. Res. 26, 461-473.
13. Cass, C. E. and Au-Yeung, T. H. (1976) Enhancement of 9-β-D-arabinofuranosyladenine cytotoxicity to mouse leukemia L1210 in vitro by 2′-deoxycoformycin. Cancer Res. 36, 1486-1491.
14. Catania, M. V., Sorino, M. A., Rampello, L., Canonico, P. L. and Nicoletti, F. (1991) Adenosine deaminase increases release of excitatory amino acids through a mechanism independent of adenosine depletion. Neuropharmacology 30, 153-159.
15. Centelles, J. J., Franco, R. and Bozal, J. (1987) Distribution of adenosine deaminase in some rat tissues: inhibition by ethanol and dimethylsulfoxide. Comp. Biochem. Physiol. 86B, 95-98.
16. Centelles, J. J., Franco, R. and Bozal, J. (1988) Purification and partial characterization of brain adenosine deaminase: inhibition by purine compounds and by drugs. J. Neurosci. Res. 19, 258-267.
17. Ciruela, F., Saura, C., Canela, E. I., Mallol, J., Lluis, C. and Franco, R. (1996) Adenosine deaminase affects ligand-induced signalling by interacting with cell surface adenosine receptors. FEBS Lett. 380, 219-223.
18. Conway, E. J. and Cooke, R. (1939) The deaminases of adenosine and adenylic acid in blood and tissues. Biochem. J. 33, 479-492.
19. Daddona, P. E., Shewach, D. S., Kelley, W. N., Argos, P., Markham, A. F. and Orkin, S. H. (1984) Human adenosine deaminase: cDNA and complete primary sequence. J. Biol. Chem. 259, 12101-12106.
20. Daly, J. W. (1977) Cyclic Nucleotides in the Nervous System. Plenum Press: New York.
21. Dalziel, H. H. and Westfall, D. P. (1994) Receptors for adenine nucleotides and nucleosides: subclassification, distribution and molecular characterization. Pharmacol. Rev. 46, 449-466.
22. Dinjens, W. N. M., van der Boon, J., ten Kate, J., Zeijlemaker, W. P., de Bruijn, C. H. M. M., Bosman, F. T. and Khan, P. M. (1986) Cell surface adenosine deaminase (ADA) and its complexing protein (ADCP) in human T-lymphoid cells. Adv. Expl Med. Biol. 195B, 407-414.
23. Dong, R.-P., Kameoka, J., Hegen, M., Tanaka. T., Xu, Y., Schlossman, S. F. and Morimoto, C. (1996) Characterization of adenosine deaminase binding human CD26 on T cells and its biologic role in immune response. J. Immunol. 156, 1349-1355.
24. Dunn, D. B. and Hall, R. H. (1975) Natural occurrence of the modified nucleosides. In: Handbook of Biochemistry and Molecular Biology, 3rd edn, pp. 65-215. Ed. G. D. Fasman. CRC Press: Cleveland.
25. 1 receptors and 5′-nucleotidase in the brain of some commonly used experimental animals. Neuroscience 22, 813-826.
26. 1 receptors in the human brain: a quantitative autoradiographic study. Neuroscience 22, 827-839.
27. Fleischer, B. (1994) CD26: a surface protease involved in T-cell activation. Immunol. Today 15, 180-184.
28. Fox, D. A., Hussey, R. E., Fitzgerald, K. A., Acuto, O., Poole, C., Palley, L., Daley, F. J., Schlossman, S. F. and Reinherz, E. L. (1984) Ta1, a novel 105 kD human T cell activation antigen defined by a monoclonal antibody. J. Immunol. 133, 1250-1256.
29. Franco, R., Canela, E. I. and Bozal, J. (1986) Heterogeneous localization of some purine enzymes in subcellular fractions of rat brain and cerebellum. Neurochem. Res. 11, 423-435.
30. Franco, R., Aran, J. M., Matutes, E., Colomer, D. and Vives-Corrons, J.-L. (1990) Association of adenosine deaminase with erythrocyte and platelet plasma membrane. An immunological study at light and electron microscopy. J. Histochem. Cytochem. 38, 653-658.
31. 1 adenosine receptors. Biochemistry 35, 3007-3015.
32. Glazer, R. I., Lott, T. J. and Peale. (1978) Potentiation by 2′-deoxycoformycin of the inhibitory effect by 3′-deoxyadenosine (cordycepin) on nuclear RNA synthesis in L1210 cells in vitro. Cancer Res. 38, 2233-2238.
33. Glazer, R. I. (1980) Adenosine deaminase inhibitors: their role in chemotherapy and immunosuppression. Cancer Chemother. Pharmacol. 4, 227-235.
34. Hall, R. H. (1975) Modified nucleosides: physical properties, chemical synthesis and natural occurrence. In: The Modified Nucleosides in Nucleic Acids, pp. 17-185. Columbia University Press: New York.
35. Hall, R. H., Alam, N. S., McLenna, B. D., Terrine, C. and Guerin, J. (1971) N6-(Δ2-isopentenyl)adenosine: its conversion to inosine, catalyzed by adenosine amino hydrolases from chicken bone marrow and calf intestinal mucosa. Can. J. Biochem. 49, 623-630.
36. Hasuo, H., Shoji, S., Gallagher, J. P. and Akasu, T. (1992) Adenosine inhibits the synaptic potentials in rat septal nucleus neurons mediated through pre- and postsynaptic A1-adenosine receptors. Neurosci. Res. 13, 281-299.
37. Hershfield, M. S. (1995) PEG-ADA replacement therapy for adenosine deaminase deficiency: an update after 8.5 years. Clin. Immunol. Immunopathol. 76, S228-S232.
38. Hershfield, M. S. and Mitchell, B. S. (1995) Immunodeficiency diseases caused by adenosine deaminase deficiency and purine nucleoside phosphorylase deficiency. In: The Metabolic and Molecular Bases of Inherited Disease, Vol. II, pp. 1725-1768. Eds C. R. Scriver, A. L. Beaudet, W. S. Sly and D. Valle. McGraw-Hill: New York.
39. Hirschhorn, R., Papageorgiou, P. S., Kesariwala, H. H. and Taft, L. T. (1980) Amelioration of neurologic abnormalities after 'enzyme replacement' in adenosine deaminase deficiency. N. Engl. J. Med. 303, 377-380.
40. Hirschhorn, R., Ratech, H., Rubinstein, A., Papageourgiou, P., Keserwala, H., Gelfand, E. and Roegner-Maniscalo, V. (1982) Increased excretion of modified adenine nucleosides by children with adenosine deaminase deficiency. Pediatr. Res. 16, 362-369.
41. 8Asn substitution results in the adenosine deaminase (ADA) genetic polymorphism (ADA-2 allozyme). Occurrence on different chromosomal backgrounds and apparent intragenic crossover. Ann. Hum. Genet. 58, 1-9.
42. Iliakis, G. and Ngo, F. Q. H. (1985) Effects of adenosine deaminase inhibitor 2′-deoxycoformycin on the repair and expression of potentially lethal damage sensitive to β-ara A. Radiat. Environ. Biophys. 24, 81-88.
43. Ingolia, D. E., Al-Ubaidi, Bigo, H. A. M. R., Kellems, R. E., Wright, D. A. and Yeung, C.-Y. (1986) Molecular cloning of the murine adenosine-deaminase gene from a genetically enriched source: identification and characterization of the promoter region. Mol. Cell. Biol. 6, 4458-4466.
44. Johns, D. G. and Adamson, R. H. (1976) Enhancement of the biological activity of cordycepin (3′-deoxyadenosine) by the adenosine deaminase inhibitor 2′-deoxycoformycin. Biochem. Pharmacol. 25, 1441-1444.
45. Johnston, J. B., Begleiter, A., Pugh, L., Leith, M. K., Wilkins, J. A., Cavers, F. D. J. and Israels, L. G. (1986) Biochemical changes induced in hairy-cell leukemia following treatment with the adenosine deaminase inhibitor 2′-deoxycoformcyin. Cancer Res. 46, 2179-2184.
46. Kameoka, J., Tanaka, T., Nojima, Y., Schlossman, S. F. and Morimoto, M. (1993) Direct association of adenosine deaminase with a T cell activation antigen CD26. Science 261, 466-469.
47. Kuroda, Y. (1978) Physiological roles of adenosine derivatives which are released during neurotransmission in mammalian brain. J. Physiol. (Lond.) 74, 463-470.
48. LePage, G. A., Worth, L. S. and Kimball, A. P. (1976) Enhancement of the antitumor activity of arabinofuranosyladenine by 2′-deoxycoformycin. Cancer Res. 36, 1481-1485.
49. 22Na uptake by rat brain synaptosomes stimulated by veratridine. J. Neurochem. 58, 1033-1037.
50. 1 adenosine receptors in brain membranes. Mol. Pharmacol. 26, 1-9.
51. Ma, D. D. F., Sylwestrowicz, T. A., Granger, S., Massaia, M., Franks, R., Janossy, G. and Hoffbrand, A. V. (1982) Distribution of terminal deoxynucleotidyl transferase and purine deagradative and synthetic enzymes in subpopulations of human thymocytes. J. Immunol. 129, 1430-1435.
52. Martin, M., Centelles, J. J., Huguet, J., Echevarne, F., Colomer, D., Vives-Corrons, J.-L. and Franco, R. (1993) Surface expression of adenosine deaminase in mitogen-stimulated lymphocytes. Clin. Expl Immunol. 93, 286-291.
53. Martin, M., Huguet, J., Centelles, J. J. and Franco, R. (1995) Expression of ectoadenosine deaminase and CD26 in human T cells triggered by the TCR-CD3 complex. Possible role of adenosine deaminase as costimulatory molecule. J. Immunol. 155, 4630-4643.
54. Massaia, M., Hoffbrand, A. V., Janossy, G., Ma, D. D., Price, G., Sylwestrowicz, T. A. and Tidman, N. (1982) Enzymes of purine metabolism in human peripheral lymphocyte subpopulations. Clin. Expl Immunol. 50, 148-154.
55. Meghji, P., Middleton, K., Hasall, C. J. S., Phillips, M. I. and Newby, A. C. (1988) Evidence for extracellular deamination of adenosine deaminase in the rat heart. Intl J. Biochem. 20, 1335-1341.
56. Migchielsen, A. A. J., Breuer, M. L., Vanroon, M. A., Riele, H. T., Zurcher, C., Ossendorp, F., Toutain, S., Hershfield, M. S., Berns, A. and Valerio, D. (1995) Adenosine-deaminase-deficient mice die perinatally and exhibit liver-cell degeneration, atelectasis and small-intestinal cell-death. Nature Genet. 10, 279-287.
57. Mills, G. C., Schmalstieg, F. C., Trimmer, K. B., Goldman, A. S. and Goldblum, R. M. (1976) Purine metabolism in adenosine deaminase deficiency. Proc. natn. Acad. Sci. U.S.A. 73, 2867-2871.
58. Miras-Portugal, M. T., Delicado, E. G., Casillas, T. and Sen, R. P. (1991) Control of nucleoside transport in neural cells. Effect of protein kinase C activation. In: Purine and Pyrimidine Metabolism in Man VII, pp. 435-438. Ed. R. A. Harkness. Plenum Press: New York.
59. Mittrücker, H.-W., Steeg, C., Malissen, B. and Fleischer, B. (1995) The cytoplasmic tail of the T cell receptor ζ chain is required for signalling via CD26. Eur. J. Immunol. 25, 295-297.
60. Nagy, J. I., LaBella, L. A., Buss, M. and Daddona, P. E. (1984) Immunohistochemistry of adenosine deaminase: implications for adenosine neurotransmission. Science 224, 166-168.
61. Nagy, J. I., Yamamoto, T. Y., Uemura, H. and Schrader, W. P. (1996) Adenosine deaminase in rodent median eminence: detection by antibody to the mouse enzyme and co-localization with adenosine deaminase-complexing protein (CD26). Neuroscience 73, 459-471.
62. O'Brien, W. J., Taylor, J. L. and Brothan, S. J. (1987) Adenosine deaminase in herpes simplex virus induced corneal stromal disease. Curr. Eye Res. 6, 13-18.
63. Olah, M. E., Ren, H. and Stiles, G. L. (1995) Adenosine receptors: protein and gene structure. Arch. Intl Pharmacodyn. Ther. 329, 135-150.
64. Oravecz, T., Pall, M. and Norcross, M. A. (1996) β-Chemokine inhibition of monocytotropic HIV-1 infection. Interference with a postbinding fusion step. J. Immunol. 157, 1329-1332.
65. Orozco, M., Canela, E. I. and Franco, R. (1990) A quantum chemical study of the enzymatic deamination of benzoadenine derivatives. A theoretical model of the interactions occurring between nucleosides and the active site of adenosine deaminase. Eur. J. Biochem. 188, 155-163.
66. Palmer, T. M. and Stiles, G. L. (1995) Adenosine receptors. Neuropharmacology 34, 683-694.
67. Petersen, M. B., Tranebjaerg, L., Tommerup, N., Nygaard, P. and Edwards, H. (1987) New assignment of the adenosine deaminase gene locus to chromosome 20q13.11 by study of a patient with interstitial deletion 20q. J. Med. Genet. 24, 93-96.
68. Phillip, T., Fraisse, J., Hamet, N., Lauras, B., Lenoir, G., Phillip, I. and Rolland, M. O. (1980) Regional assignment of the ADA locus 20q 13.2 qtr by gene dosage studies. Cytogenet. Cell Genet. 27, 187-189.
69. Phillis, J. W. and Wu, P. H. (1981) The role of adenosine and its nucleotides in central synaptic transmission. Progr. Neurobiol. 16, 187-239.
70. Proctor, W. R. and Dunwiddie, T. V. (1987) Pre- and postsynaptic actions of adenosine in the in vitro rat hippocampus. Brain Res. 426, 187-190.
71. 1 adenosine receptors in pig brain cortical membranes. J. Neurochem. 66, 675-682.
72. Sayós, J., Blanco, J., Ciruela, F., Canela, E. I., Mallol, J., Lluis, C. and Franco, R. (1994) Regulation of nitrobenzylthioinosine-sensitive adenosine uptake by cultured kidney cells. Am. J. Physiol. 257, F758-F766.
73. Schrader, W. P., West, C. A. and Stromiger, N. L. (1987) Localization of adenosine deaminase complexing protein in rabbit brain. J. Histochem. Cytochem. 35, 443-451.
74. Schubert, P., Lee, K. and Kreutberg, G. W. (1986) Neuromodulation by adenosine and the effect on ion fluxes. Expl Brain Res. Ser. 14, 236-244.
75. Schubert, P., Rudolphi, K. A., Fredholm, B. B. and Nakamura, Y. (1994) Modulation of nerve and glial function by adenosine. Intl J. Biochem. 26, 1227-1236.
76. Senesi, S., Freer, G., Gasperini, M., Batoni, G. and Campa, M. (1988) Complete release of adenosine deaminase from mouse lymphocytes stabilized by low-pH acetate. Biochim. Biophys. Acta 968, 59-68.
77. Smyth, J. F., Prentice, H. G., Proctor, S. and Hoffbrand, A. V. (1985) Deoxycoformcyin in the treatment of leukemias and lymphomas. Ann. NY Acad. Sci. 451, 123-128.
78. Spiers, A. S. D. (1985) The activity of deoxycoformycin (pentostatin) in refractory leukemias and lymphomas. Ann. NY Acad. Sci. 451, 138-141.
79. Spencer, N., Hopkinson, D. A. and Harris, H. (1968) Adenosine deaminase polymorphism in man. Ann. Hum. Genet. 32, 9-14.
80. Thompson, R. E., Piper, D. J., Galberg, C., Chan, T. H., Tolkoff-Rubin, N. E. and Rubin, R. H. (1985a) Adenosine deaminase binding protein, a new diagnostic marker for kidney disease. Clin. Chem. 31, 679-683.
81. Thompson, R. E., Hewitt, C. R., Piper, D. J., Hansen, P., Rubin, R. H., Tolkoff-Rubin, N. E., Barret, M. C. and Nelles, M. J. (1985b) Competitive idiotype-anti-idiotype immunoassay for adenosine deaminase binding protein in urine. Clin. Chem. 31, 1833-1837.
82. Tischfield, J. A., Creagan, R. P., Nichols, E. A. and Ruddle, F. H. (1974) Assignment of a gene for adenosine deaminase to human chromosome 20. Hum. Hered. 24, 1-11.
83. Thorn, J. A. and Jarvis, S. M. (1996) Adenosine transporters. Gen. Pharmacol. 27, 613-620.
84. Torimoto, Y., Dang, N. H., Vivier, E., Tanaka, T., Schlossman, S. F. and Morimoto, C. (1991) Coassociation of CD26 (dipeptidyl peptidase IV) with CD45 on the surface of human T lymphocytes. J. Immunol. 147, 2514-2517.
85. Torres, M., Delicado, E. G., Fideu, M. D. and Miras-Portugal, M. T. (1992) Down-regulation and recycling of the nitrobenzylthioinosine-sensitive nucleoside transporter in cultured chrmaffin cells. Biochim. Biophys. Acta 1105, 291-299.
86. Trams, E. G. and Lauter, C. J. (1975) Adenosine deaminase of cultured brain cells. Biochem. J. 152, 681-687.
87. Trotta, P. P. and Balis, M. E. (1977) Structural and kinetic alterations in adenosine deaminase associated with the differentiation of rat intestinal cells. Cancer Res. 37, 2297-2305.
88. Tucker, A. L. and Linden, J. (1993) Cloned receptors and cardiovascular responses to adenosine. Cardiovasc. Res. 27, 62-67.
89. 2 receptors differentially modulates calcium channels and glycinergic synaptic transmission in rat brainstem. Neuron 13, 1439-1446.
90. Valenzuela, A., Blanco, J., Callebaut, C., Jacotot, E., Lluis, C., Hovanessian, A. and Rafael, F. (1997) Adenosine deaminase binding to human CD26 is inhibited by HIV-1 envelope gp120 and viral particles. J. Immunol. 158, 3721-3729.
91. Valerio, D., McIvor, R. S., Williams, S. R., Duyvesteyn, M. G. C., Van Ormondt, H., Van der Eb, A. J. and Martin, D. W. Jr. (1984) Cloning of human adenosine deaminase cDNA and expression in mouse cells. Gene 31, 147-153.
92. Van der Weyden, M. B. and Kelley, W. N. (1976) Human adenosine deaminase: distribution and properties. J. Biol. Chem. 251, 5448-5456.
93. Vives-Corrons, J. L., Rozman, C., Pujades, M. A., Colomer, D., Pérez-Vila, E., Anegon, I., Gallart, T., Vives-Puiggros, J., Viñolas, N. and Montserrat, E. (1988) Combined assay of adenosine deaminase, purine nucleoside phosphorylase and lactate dehydrogenase in the early clinical evaluation of B-chronic lymphocytic leukemia. Am. J. Hematol. 27, 157-162.
94. Wakamiya, M., Blackburn, M. R., Jurecic, R., McArthur, M. J., Geske, R. S., Cartwright, J., Mitani, K., Vaishnav, S., Belmont, J. W., Kellems, R. W., Finegold, M. J., Montgomery, C. A., Bradley, A. and Caskey, C. T. (1995) Disruption of the adenosine-deaminase gene causes hepatocellular impairment and perinatal lethality in mice. Proc. natn. Acad. Sci. U.S.A. 92, 3673-3677.
95. Wiginton, D. A., Coleman, M. S. and Hutton, J. J. (1981) Purification, characterization and radioimmunoassay of adenosine deaminase from human leukaemic granulocytes. Biochem. J. 195, 389-397.
96. Wiginton, D. A., Adrian, G. S. and Hutton, J. J. (1984) Sequence of human adenosine deaminase. cDNA including the coding region and a small intron. Nucl. Acid Res. 12, 2439-2446.
97. Wiginton, D. A., Kaplan, D. J., States, J. C., Akeson, A. L., Perme, C. M., Bilyk, I. J., Vaighn, A. J., Lattier, D. L. and Hutton, J. J. (1986) Complete sequence and structure of the gene for human adenosine deaminase. Biochemistry 25, 8234-8244.
98. 3H]-adenosine, a stable analog of adenosine. Proc. natn. Acad. Sci. U.S.A. 77, 6892-6896.
99. Williams, M. and Risley, E. (1980b) High affinity binding of 2-chloroadenosine to rat brain synaptic membrames. Eur. J. Pharmacol. 64, 369-370.
100. Wilson, D. K., Rudolph, F. B. and Quiocho, F. A. (1991) Atomic structure of adenosine deaminase complexed with a transition-state analog: understanding catalysis and immunodeficiency mutations. Science 252, 1278-1284.
101. Wilson, D. K. and Quiocho, F. A. (1993) A pre-transition-state mimic of an enzyme X-ray structure of adenosine-deaminase with bound 1-deazaadenosine and zinc-activated water. Biochemistry 32, 1689-1694.
102. 3H]-2-chloroadenosine. Intl J. Biochem. 14, 399-402.
103. 3H]-chloroadenosine to rat brain cortical membranes. Can. J. Physiol. Pharmacol. 58, 576-579.
104. Zielke, C. L. and Suelter, C. H. (1971) Purine, purine nucleoside nad purine nucleotide amino hydrolases. In: The Enzymes, Vol. 4, pp. 54-364. Ed P. D. Boyer. Academic Press: New York.