Purification of trans-N-glycosidase of Thermobacter acidophilus: Inhibition of enzyme by 6-azathymidine

Marsh, Jane; King, Mary E.

doi:10.1016/0006-2952(59)90081-4

Cited by 22 publications

(6 citation statements)

References 12 publications

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“…However, 2,6-diaminopurine was reported to give negative results with extracts of L. helveticus [l], Thermobacter acidophilus [6] and L. kichmanii [7]. It was found to be a competent substrate with extracts of L. delbruecki [7].…”

Section: Tliivd Conclusionmentioning

confidence: 99%

“…If our conclusions are correct, 2,6-diaminopurine is expected to be a substrate. The 8-aza derivatives were sometimes found to be substrates: S-azaguanine with L. helveticus [3], L. delbruecki [4], and T. acidophilus [6], 8-aza-adenine with T. acidophilus [6] and L. helvcticus [9], 8-aza-xanthine with L. helveticus [3], but in some instances gave negative results: 8-aza-xanthine with T. acidophilus [6]. Our preparation was active on all three compounds in accordance with our hypothesis, but 8-aza-xanthine reacted very slowly or had a very low equilibrium constant.…”

Section: Tliivd Conclusionmentioning

confidence: 99%

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Trans‐N‐Deoxyribosylase: Substrate Specificity Studies

Holguín

Cardinaud

Salemink³

1975

European Journal of Biochemistry

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A series of purine bases and analogues were tested as substrates for trans-N-deoxyribosylase (EC 2.4.2.6). It was observed that the pyrimidine ring and its substituents on positions 1 , 2 and 6, are of minor importance. On the other hand only a few modifications are tolerated on the imidazole moiety, as follows.1. A tautomeric proton must be present on the imidazole ring. The "usual" shift is between position 9 and 7.2. The position of the tautomeric proton governs the site of substitution. 3 . For steric reasons no substituent is allowed on position 8.The direct transfer of the deoxyribosyl moiety from a purine (or a pyrimidine) deoxyribonucleoside to a purine (or pyrimidine) base is catalyzed by trans-N-deoxyribosylase [l]. The presence of this enzyme seems to be limited to a few bacteria species in the Lactobacillus genus. In a previous report it was shown that trans-N-deoxyribosylase from Lactobacillus helveticus is made up of at least two different enzymes [2]. trans-N-Deoxyribosylase-I specifically catalyzes the transfer between purine bases. trans-N-Deoxyribosylase-I1 catalyzes the (Pur $ Pyr) transfer. Since this transfer proceeds via a ping-pong bi-bi mechanism it is expected that the (Pur z $ Pur) and (Pyr + Pyr) transfers will also be observed. Information concerning the specificity of trans-N-deoxyribosylase appears in a number of reports, some of which are relevant to the present study [1,. In spite of a few conflicting results the broad specificity of transAbbreviutions. Pur, a purine base; Pyr, a pyrimidine base; (Pur + Pyr) is a transfer reaction where the deoxyribosyl moiety is transferred from a purine to a pyrimidine ; deoxyribonucleosides are abbreviated as recommended by IUPAC-IUB; (dIno + Ade) denotes a transfer in which deoxy inosine and adenine are the substrates.Enzyme. trans-N-Deoxyribosylase or nucleoside : purine (pyrimidine) deoxyribosyl transferase (EC 2.4.2.6).N-deoxyribosylase for the acceptor base is unanimously accepted. Using a pyrimidine deoxyribonucleoside as donor and a purine base as acceptor we were able to study the specificity of the acceptor base for trans-N-deoxyribosylase-11. In the present report we make a first attempt to give the structural requirements necessary for a purine base to be a competent acceptor in the (dRib-Pyr --+ Pur) transfer. MATERIALS AND METHODS ReagentsSome of the purine bases used in this study were commercial products from Aldrich, Sigma, Fluka, Cyclo, Schwarz-Mann or Calbiochem. The purity was checked by : (a) thin-layer chromatography on cellulose MN 300 (Macherey & Nagel) using six different solvents [12]; (b) absorption spectroscopy in the ultraviolet or visible range when the spectrum could be found in the literature for comparison [13].When a base gave several spots by thin-layer chromatography a purification was attempted by Eur.

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Section: Tliivd Conclusionmentioning

confidence: 99%

Section: Tliivd Conclusionmentioning

confidence: 99%

Trans‐N‐Deoxyribosylase: Substrate Specificity Studies

Holguín

Cardinaud

Salemink³

1975

European Journal of Biochemistry

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“…In most bacteria, deoxyribosyl transfer between purines and pyrimidines is catalyzed by the coupled action of purine nucleoside phosphorylase and thymidine phosphorylase (197). However, Lactobacilli have acquired a specific enzyme, trans-N-deoxyribosylase, which catalyzes a phosphate independent transfer of deoxyribose moieties between a wide variety of purines and pyrimidines (equation XXII; references 35, 207,259,263,270,339).…”

Section: Enzymesmentioning

confidence: 99%

“…dine, but does not itself serve as a deoxyribose donor for the enzyme (67,263). Since 6-azathymidine also inhibits organisms which lack the enzyme trans-N-deoxyribosylase, this is obviously not the primary site of action of 6-azathymidine (67).…”

Section: Downloaded Frommentioning

confidence: 99%

Pyrimidine metabolism in microorganisms.

O’Donovan¹,

Neuhard²

1970

Bacteriological Reviews

304

180

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“…The poor uptake and incorporation of thymine by L. acidophilus even in the presence of purine deoxyribosides (Table 3) may be due to the absence of a thymidine phosphorylase strong enough to synthesize thymidine from thymine. However, L. acidophilus contains a trans-N-glycosidase which catalyzes an exchange between deoxyyibonucleosides and a wide variety of purines and pyrimidines (1,16,(19)(20)(21)28). In the presence of deoxyguanosine, thymine should be readily incorporated into DNA via transglycosylation of thymine to thymidine unless the transglycosylating activity is weak in this organism, or the K,,, for thymine is very high, and any thymidine formed is broken down by thymidinedegradative enzymes (29).…”

Section: Discussionmentioning

confidence: 99%

Participation of exogenous thymine and thymidine in deoxyribonucleic acid synthesis in Lactobacillus acidophilus

Sawula¹,

Zamenhof²,

Zamenhof³

1975

Can. J. Microbiol.

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The degree of participation (DP) of exogenous thymidine and thymine in overall DNA synthesis was studied in Lactobacillus acidophilus R-26. The DP of thymidine remains constant under a variety of conditions (except at low thymidine concentrations, when the DP is influenced by deoxyribonucleosides and folic acid). A 5-bromodeoxyuridine-resistant mutant was isolated, which displayed cross-resistance to 5-bromouracil and a significantly lower DP of thymidine than the parental strain. Thymine was poorly incorporated in the parental strain even in the presence of deoxyribosides. The results of this investigation would be compatible with the possibility of an alternative pathway for thymidylate synthesis other than the known thymidylate synthase pathway.

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Purification of trans-N-glycosidase of Thermobacter acidophilus: Inhibition of enzyme by 6-azathymidine

Cited by 22 publications

References 12 publications

Trans‐N‐Deoxyribosylase: Substrate Specificity Studies

Trans‐N‐Deoxyribosylase: Substrate Specificity Studies

Pyrimidine metabolism in microorganisms.

Participation of exogenous thymine and thymidine in deoxyribonucleic acid synthesis in Lactobacillus acidophilus

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