|
|
| Enzyme Name | | Swiss-prot | KEGG |
|---|
| P03958 | P56658 |
|---|
| Protein name | Adenosine deaminase | Adenosine deaminase | adenosine deaminasedeoxyadenosine deaminase |
|---|
| Synonyms | EC 3.5.4.4Adenosine aminohydrolase | EC 3.5.4.4Adenosine aminohydrolase |
|---|
| KEGG pathways | | MAP code | Pathways |
|---|
| MAP00230 | Purine metabolism |
| Swiss-prot:Accession Number | P03958 | P56658 |
|---|
| Entry name | ADA_MOUSE | ADA_BOVIN |
|---|
| Activity | Adenosine + H(2)O = inosine + NH(3). | Adenosine + H(2)O = inosine + NH(3). |
|---|
| Subunit |
|
|
|---|
| Subcellular location |
|
|
|---|
| Cofactor |
|
|
|---|
| Cofactors | Substrates | Products | intermediates |
|---|
| KEGG-id | C00038 | C00212 | C00001 | C00294 | C00014 | I00018 |
|---|
| Compound | Zinc | Adenosine | H2O | Inosine | NH3 | 6-Hydroxy-adenosine |
|---|
| Type | heavy metal | amine group,nucleoside | H2O | amide group,nucleoside | amine group,organic ion |
|
|---|
| 1a4lA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:DCF |
|---|
| 1a4lB |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:DCF |
|---|
| 1a4lC |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:DCF |
|---|
| 1a4lD |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:DCF |
|---|
| 1a4mA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:PRH |
|---|
| 1a4mB |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:PRH |
|---|
| 1a4mC |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:PRH |
|---|
| 1a4mD |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:PRH |
|---|
| 1addA |  | Bound:_ZN | Analogue:1DA | Bound:HOH 461 | Unbound | Unbound | Unbound |
|---|
| 1fkwA |  | Bound:_ZN | Analogue:PUR |
| Unbound | Unbound | Unbound |
|---|
| 1fkxA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:PRH |
|---|
| 1uioA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:HPR |
|---|
| 1uipA |  | Bound:_ZN | Analogue:PUR |
| Unbound | Unbound | Unbound |
|---|
| 2adaA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:HPR |
|---|
| 1krmA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Intermediate-analogue:PRH |
|---|
| 1ndvA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1ndwA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1ndyA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1ndzA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1o5rA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1qxlA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1umlA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1v78A |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1v79A |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1v7aA |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1w1iE |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1w1iF |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1w1iG |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 1w1iH |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 2bgnE |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 2bgnF |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 2bgnG |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| 2bgnH |  | Bound:_ZN | Unbound |
| Unbound | Unbound | Unbound |
|---|
| References for Catalytic Mechanism | | References | Sections | No. of steps in catalysis |
|---|
| [1] | p.8455-8456 |
| | [2] | p.7382-7383 |
| | [4] | p.1246-1247 |
| | [6] | Fig.4, p.1282-1283 |
| | [7] | p.7364-7365 |
| | [10] | Fig.3, p.1692-1693 |
| | [11] | p.693 |
| | [12] |
|
| | [13] | Scheme 1 |
| | [14] | Fig.1, p.7863, p.7871 |
| | [15] | Fig.1, p.15027-15028 |
| | [19] | p.4974-4975 |
| | [20] | p.8322-8323 |
| | [22] | p.2589-2590 |
|
| references | | [1] |
|---|
| PubMed ID | 3442668 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1987 |
|---|
| Volume | 26 |
|---|
| Pages | 8450-7 |
|---|
| Authors | Kurz LC, Frieden C |
|---|
| Title | Adenosine deaminase converts purine riboside into an analogue of a reactive intermediate: a 13C NMR and kinetic study. |
|---|
| [2] |
|---|
| PubMed ID | 3427079 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1987 |
|---|
| Volume | 26 |
|---|
| Pages | 7378-84 |
|---|
| Authors | Weiss PM, Cook PF, Hermes JD, Cleland WW |
|---|
| Title | Evidence from nitrogen-15 and solvent deuterium isotope effects on the chemical mechanism of adenosine deaminase. |
|---|
| [3] |
|---|
| PubMed ID | 3398052 |
|---|
| Journal | J Mol Biol |
|---|
| Year | 1988 |
|---|
| Volume | 200 |
|---|
| Pages | 613-4 |
|---|
| Authors | Wilson DK, Rudolph FB, Harrison ML, Kellems RE, Quiocho FA |
|---|
| Title | Preliminary X-ray analysis of crystals of murine adenosine deaminase. |
|---|
| [4] |
|---|
| PubMed ID | 2713361 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1989 |
|---|
| Volume | 28 |
|---|
| Pages | 1242-7 |
|---|
| Authors | Jones W, Kurz LC, Wolfenden R |
|---|
| Title | Transition-state stabilization by adenosine deaminase: 1,6-addition of water to purine ribonucleoside, the enzyme's affinity for 6-hydroxy-1,6-dihydropurine ribonucleoside, and the effective concentration of substrate water at the active site. |
|---|
| [5] |
|---|
| PubMed ID | 2275794 |
|---|
| Journal | J Biomol Struct Dyn |
|---|
| Year | 1990 |
|---|
| Volume | 8 |
|---|
| Pages | 199-212 |
|---|
| Authors | Cox MB, Arjunan P, Arora SK |
|---|
| Title | Structural and conformational analysis of pentostatin (2'-deoxycoformycin), a potent inhibitor of adenosine deaminase. |
|---|
| [6] |
|---|
| Comments | X-RAY CRYSTALLOGRAPHY (2.4 ANGSTROMS). |
|---|
| Medline ID | 92022516 |
|---|
| PubMed ID | 1925539 |
|---|
| Journal | Science |
|---|
| Year | 1991 |
|---|
| Volume | 252 |
|---|
| Pages | 1278-84 |
|---|
| Authors | Wilson DK, Rudolph FB, Quiocho FA |
|---|
| Title | Atomic structure of adenosine deaminase complexed with a transition-state analog: understanding catalysis and immunodeficiency mutations. |
|---|
| Related PDB | 2ada |
|---|
| Related Swiss-prot | P03958 |
|---|
| [7] |
|---|
| PubMed ID | 1510925 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1992 |
|---|
| Volume | 31 |
|---|
| Pages | 7356-66 |
|---|
| Authors | Kati WM, Acheson SA, Wolfenden R |
|---|
| Title | A transition state in pieces: major contributions of entropic effects to ligand binding by adenosine deaminase. |
|---|
| [8] |
|---|
| PubMed ID | 1731884 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1992 |
|---|
| Volume | 31 |
|---|
| Pages | 39-48 |
|---|
| Authors | Kurz LC, Moix L, Riley MC, Frieden C |
|---|
| Title | The rate of formation of transition-state analogues in the active site of adenosine deaminase is encounter-controlled: implications for the mechanism. |
|---|
| [9] |
|---|
| PubMed ID | 1518061 |
|---|
| Journal | J Mol Biol |
|---|
| Year | 1992 |
|---|
| Volume | 226 |
|---|
| Pages | 917-21 |
|---|
| Authors | Sharff AJ, Wilson DK, Chang Z, Quiocho FA |
|---|
| Title | Refined 2.5 A structure of murine adenosine deaminase at pH 6.0. |
|---|
| [10] |
|---|
| Comments | X-ray crystallography |
|---|
| PubMed ID | 8439534 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1993 |
|---|
| Volume | 32 |
|---|
| Pages | 1689-94 |
|---|
| Authors | Wilson DK, Quiocho FA |
|---|
| Title | A pre-transition-state mimic of an enzyme: X-ray structure of adenosine deaminase with bound 1-deazaadenosine and zinc-activated water. |
|---|
| Related PDB | 1add |
|---|
| [11] |
|---|
| PubMed ID | 7634072 |
|---|
| Journal | Nat Struct Biol |
|---|
| Year | 1994 |
|---|
| Volume | 1 |
|---|
| Pages | 691-4 |
|---|
| Authors | Wilson DK, Quiocho FA |
|---|
| Title | Crystallographic observation of a trapped tetrahedral intermediate in a metalloenzyme. |
|---|
| [12] |
|---|
| PubMed ID | 8634299 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1996 |
|---|
| Volume | 35 |
|---|
| Pages | 1672-80 |
|---|
| Authors | Mohamedali KA, Kurz LC, Rudolph FB |
|---|
| Title | Site-directed mutagenesis of active site glutamate-217 in mouse adenosine deaminase. |
|---|
| [13] |
|---|
| PubMed ID | 8664259 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1996 |
|---|
| Volume | 35 |
|---|
| Pages | 4697-703 |
|---|
| Authors | Shih P, Wolfenden R |
|---|
| Title | Enzyme-substrate complexes of adenosine and cytidine deaminases: absence of accumulation of water adducts. |
|---|
| [14] |
|---|
| Comments | X-ray crystallography |
|---|
| PubMed ID | 8672487 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1996 |
|---|
| Volume | 35 |
|---|
| Pages | 7862-72 |
|---|
| Authors | Sideraki V, Mohamedali KA, Wilson DK, Chang Z, Kellems RE, Quiocho FA, Rudolph FB |
|---|
| Title | Probing the functional role of two conserved active site aspartates in mouse adenosine deaminase. |
|---|
| Related PDB | 1fkw,1fkx |
|---|
| [15] |
|---|
| Comments | X-RAY CRYSTALLOGRAPHY (2.4 ANGSTROMS). |
|---|
| Medline ID | 97098127 |
|---|
| PubMed ID | 8942668 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1996 |
|---|
| Volume | 35 |
|---|
| Pages | 15019-28 |
|---|
| Authors | Sideraki V, Wilson DK, Kurz LC, Quiocho FA, Rudolph FB |
|---|
| Title | Site-directed mutagenesis of histidine 238 in mouse adenosine deaminase: substitution of histidine 238 does not impede hydroxylate formation. |
|---|
| Related PDB | 1uio,1uip |
|---|
| Related Swiss-prot | P03958 |
|---|
| [16] |
|---|
| PubMed ID | 9442929 |
|---|
| Journal | Biochem Mol Biol Int |
|---|
| Year | 1997 |
|---|
| Volume | 43 |
|---|
| Pages | 1339-52 |
|---|
| Authors | Lupidi G, Marmocchi F, Venardi G, Cristalli G |
|---|
| Title | Functional residues at the active site of bovine brain adenosine deaminase. |
|---|
| [17] |
|---|
| PubMed ID | 9361033 |
|---|
| Journal | Hum Mol Genet |
|---|
| Year | 1997 |
|---|
| Volume | 6 |
|---|
| Pages | 2271-8 |
|---|
| Authors | Jiang C, Hong R, Horowitz SD, Kong X, Hirschhorn R |
|---|
| Title | An adenosine deaminase (ADA) allele contains two newly identified deleterious mutations (Y97C and L106V) that interact to abolish enzyme activity. |
|---|
| [18] |
|---|
| PubMed ID | 9341908 |
|---|
| Journal | J Med Chem |
|---|
| Year | 1997 |
|---|
| Volume | 40 |
|---|
| Pages | 3336-45 |
|---|
| Authors | Groziak MP, Huan ZW, Ding H, Meng Z, Stevens WC, Robinson PD |
|---|
| Title | Effect of a chemical modification on the hydrated adenosine intermediate produced by adenosine deaminase and a model reaction for a potential mechanism of action of 5-aminoimidazole ribonucleotide carboxylase. |
|---|
| [19] |
|---|
| PubMed ID | 9538015 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1998 |
|---|
| Volume | 37 |
|---|
| Pages | 4968-76 |
|---|
| Authors | Deng H, Kurz LC, Rudolph FB, Callender R |
|---|
| Title | Characterization of hydrogen bonding in the complex of adenosine deaminase with a transition state analogue: a Raman spectroscopic study. |
|---|
| [20] |
|---|
| Comments | X-RAY CRYSTALLOGRAPHY (2.6 ANGSTROMS). |
|---|
| Medline ID | 98285559 |
|---|
| PubMed ID | 9622483 |
|---|
| Journal | Biochemistry |
|---|
| Year | 1998 |
|---|
| Volume | 37 |
|---|
| Pages | 8314-24 |
|---|
| Authors | Wang Z, Quiocho FA |
|---|
| Title | Complexes of adenosine deaminase with two potent inhibitors: X-ray structures in four independent molecules at pH of maximum activity. |
|---|
| Related PDB | 1a4l,1a4m |
|---|
| Related Swiss-prot | P03958 |
|---|
| [21] |
|---|
| PubMed ID | 9474762 |
|---|
| Journal | Biophys Chem |
|---|
| Year | 1998 |
|---|
| Volume | 70 |
|---|
| Pages | 41-56 |
|---|
| Authors | Caiolfa VR, Gill D, Parola AH |
|---|
| Title | Probing the active site of adenosine deaminase by a pH responsive fluorescent competitive inhibitor. |
|---|
| [22] |
|---|
| PubMed ID | 10704207 |
|---|
| Journal | Biochemistry |
|---|
| Year | 2000 |
|---|
| Volume | 39 |
|---|
| Pages | 2581-92 |
|---|
| Authors | Ford H Jr, Dai F, Mu L, Siddiqui MA, Nicklaus MC, Anderson L, Marquez VE, Barchi JJ Jr |
|---|
| Title | Adenosine deaminase prefers a distinct sugar ring conformation for binding and catalysis: kinetic and structural studies. |
|---|
| [23] |
|---|
| PubMed ID | 10673097 |
|---|
| Journal | Bioorg Med Chem Lett |
|---|
| Year | 2000 |
|---|
| Volume | 10 |
|---|
| Pages | 139-41 |
|---|
| Authors | Tritsch D, Jung PM, Burger A, Biellmann JF |
|---|
| Title | 3'-Beta-ethynyl and 2'-deoxy-3'-beta-ethynyl adenosines: first 3'-beta-branched-adenosines substrates of adenosine deaminase. |
|---|
| [24] |
|---|
| PubMed ID | 12057661 |
|---|
| Journal | Bioorg Med Chem |
|---|
| Year | 2002 |
|---|
| Volume | 10 |
|---|
| Pages | 2723-30 |
|---|
| Authors | Hernandez S, Ford H Jr, Marquez VE |
|---|
| Title | Is the anomeric effect an important factor in the rate of adenosine deaminase catalyzed hydrolysis of purine nucleosides? A direct comparison of nucleoside analogues constructed on ribose and carbocyclic templates with equivalent heterocyclic bases selected to promote hydration. |
|---|
| [25] |
|---|
| PubMed ID | 11901152 |
|---|
| Journal | J Biol Chem |
|---|
| Year | 2002 |
|---|
| Volume | 277 |
|---|
| Pages | 19720-6 |
|---|
| Authors | Richard E, Alam SM, Arredondo-Vega FX, Patel DD, Hershfield MS |
|---|
| Title | Clustered charged amino acids of human adenosine deaminase comprise a functional epitope for binding the adenosine deaminase complexing protein CD26/dipeptidyl peptidase IV. |
|---|
| [26] |
|---|
| PubMed ID | 12437375 |
|---|
| Journal | J Biomol Struct Dyn |
|---|
| Year | 2002 |
|---|
| Volume | 20 |
|---|
| Pages | 375-80 |
|---|
| Authors | Anderson E, Britt BM |
|---|
| Title | The stability curve of bovine adenosine deaminase is bimodal. |
|---|
| [27] |
|---|
| Comments | X-ray crystallography |
|---|
| PubMed ID | 12554940 |
|---|
| Journal | Acta Crystallogr D Biol Crystallogr |
|---|
| Year | 2003 |
|---|
| Volume | 59 |
|---|
| Pages | 299-303 |
|---|
| Authors | Kinoshita T, Nishio N, Nakanishi I, Sato A, Fujii T |
|---|
| Title | Structure of bovine adenosine deaminase complexed with 6-hydroxy-1,6-dihydropurine riboside. |
|---|
| Related PDB | 1krm |
|---|
| [28] |
|---|
| PubMed ID | 12643924 |
|---|
| Journal | Bioorg Med Chem Lett |
|---|
| Year | 2003 |
|---|
| Volume | 13 |
|---|
| Pages | 1115-8 |
|---|
| Authors | Terasaka T, Nakanishi I, Nakamura K, Eikyu Y, Kinoshita T, Nishio N, Sato A, Kuno M, Seki N, Sakane K |
|---|
| Title | Structure-based de novo design of non-nucleoside adenosine deaminase inhibitors. |
|---|
| [29] |
|---|
| Comments | X-ray crystallography |
|---|
| PubMed ID | 14709046 |
|---|
| Journal | J Am Chem Soc |
|---|
| Year | 2004 |
|---|
| Volume | 126 |
|---|
| Pages | 34-5 |
|---|
| Authors | Terasaka T, Kinoshita T, Kuno M, Nakanishi I |
|---|
| Title | A highly potent non-nucleoside adenosine deaminase inhibitor: efficient drug discovery by intentional lead hybridization. |
|---|
| Related PDB | 1ndv,1ndw,1ndy,1ndz |
|---|
| [30] |
|---|
| Comments | X-ray crystallography |
|---|
| PubMed ID | 15213224 |
|---|
| Journal | J Biol Chem |
|---|
| Year | 2004 |
|---|
| Volume | 279 |
|---|
| Pages | 43330-5 |
|---|
| Authors | Weihofen WA, Liu J, Reutter W, Saenger W, Fan H |
|---|
| Title | Crystal structure of CD26/dipeptidyl-peptidase IV in complex with adenosine deaminase reveals a highly amphiphilic interface. |
|---|
| Related PDB | 1w1i |
|---|
| [31] |
|---|
| Comments | X-ray crystallography |
|---|
| PubMed ID | 15239652 |
|---|
| Journal | J Med Chem |
|---|
| Year | 2004 |
|---|
| Volume | 47 |
|---|
| Pages | 3730-43 |
|---|
| Authors | Terasaka T, Kinoshita T, Kuno M, Seki N, Tanaka K, Nakanishi I |
|---|
| Title | Structure-based design, synthesis, and structure-activity relationship studies of novel non-nucleoside adenosine deaminase inhibitors. |
|---|
| Related PDB | 1o5r,1uml,1qxl |
|---|
| [32] |
|---|
| Comments | X-ray crystallography |
|---|
| PubMed ID | 15139750 |
|---|
| Journal | J Med Chem |
|---|
| Year | 2004 |
|---|
| Volume | 47 |
|---|
| Pages | 2728-31 |
|---|
| Authors | Terasaka T, Okumura H, Tsuji K, Kato T, Nakanishi I, Kinoshita T, Kato Y, Kuno M, Seki N, Naoe Y, Inoue T, Tanaka K, Nakamura K |
|---|
| Title | Structure-based design and synthesis of non-nucleoside, potent, and orally bioavailable adenosine deaminase inhibitors. |
|---|
| Related PDB | 1v78,1v79,1v7a |
|---|
| [33] |
|---|
| Comments | X-ray crystallography |
|---|
| PubMed ID | 15695814 |
|---|
| Journal | J Biol Chem |
|---|
| Year | 2005 |
|---|
| Volume | [Epub ahead of print] |
|---|
| Pages | [Epub ahead of print] |
|---|
| Authors | Weihofen WA, Liu J, Reutter W, Saenger W, Fan H |
|---|
| Title | Crystal structures of HIV-1 Tat derived nonapeptides Tat(1-9) and Trp2-Tat(1-9) bound to the active site of dipeptidyl peptidase IV (CD26). |
|---|
| Related PDB | 2bgn |
|---|
| comments | This enzyme belongs to the adenosine and AMP deaminase family. This enzyme is homologous to guanine deaminase (EC 3.5.4.3; D00873 in EzCatDB) and cytosine deaminase (EC 3.5.4.1; D00675 in EzCatDB), sharing a similar catalytic site. This enzyme catalyzes two successive reactions (as in cytidine deaminase (D00406 in EzCatDB), according to the literature [6], [10] & [20]. (A) Additive double-bond deformation; Addition of water to purine C6-carbon to form a tetrahedral intermediate (I00018). (B) Eliminative double-bond formation; Elimination of amine group from the intermediate, forming a carbonyl group. #### Although literature [10] suggested that His238 is a general base to activate the water in the first reaction (A), other papers gave the evidence against it. Instead of His238, Asp295 seems more likely base (see [6], [14] & [15]). Moreover, in the second reaction, some papers ([14] & [15]) suggested that His238 might act as a general acid to protonate the eliminated amine group, it is too distant from the group. Instead of the residue, hydrophobic cluster composed of Leu58, Phe61, Thr269 & Phe300 seems to facilitate the elimination (see [20]). However, these hydrophobic residues are not so conserved among the homologous enzymes (guanine deaminase and cytosine deaminase). In analogy with cytosine deaminase (D00675 in EzCatDB), which adopts Fe2+ ion as cofactor, and guanine deaminase, which uses the same cofactor, zinc ion, as this enzyme, this enzyme may catalyzes the following reactions (addition and elimination): (A) Additive double-bond deformation; Addition of water to purine C6-carbon, forming a tetrahedral intermediate (I00018): (A1) Asp295 acts as a general base to deprotonate the Zinc-bound water. Here, the positive charge of His238 seems to stabilize the activated water. (A2) The activated water makes a nucleophilic attack on the C6 atom, whilst Glu217 acts as a general acid to protonate the N1 atom (protonation site) of the purine. This reaction leads to the formation of tetrahedral intermediate at the C6 atom, transforming the N1-C6 bond from double bond to single bond (I00018). (B) Eliminative double-bond formation; Elimination of amine group from the intermediate, forming a carbonyl group. (B1) Asp295 acts as a general acid to protonate the eliminated amine group, releasing the ammonia. (B2) Asp295 acts as a general base to deprotonate the hydroxyl group, bound to the zinc ion and His238. (Here, His238 may assist the catalytic function of Asp295 as well.) This reaction leads to the enol form of the product, inosine. (This may be an E1-like reaction, as amine elimination occurs prior to deprotonation.)
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| created | updated |
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| 2005-03-22 | 2012-10-17 |
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