Mechanistic Investigation of Phenylalanine Ammonia Lyase by Using <i>N</i>‐Methylated Phenylalanines

Viergutz, Sandra; Poppe, László; Tomin, Anna; Rétey, János

doi:10.1002/hlca.200390305

Cited by 8 publications

(18 citation statements)

References 32 publications

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“…All the active‐site residues in the PAL model occupy positions that would be expected on the basis of comparison with the HAL sequence and structure. Moreover, the model constructed for the PAL from Petroselinum crispum 86 ( Pc‐ PAL; Figure 6, right) shows excellent similarity with the recently published X‐ray crystal structures of the PAL from Rhodosporidium toruloides 49a ( Rt ‐PAL; Figure 6, middle column; PDB codes for Rt ‐PAL: 1T6J and 1T6P) and Pc ‐PAL 49b…”

Section: The Active Sites Of Hal and Palsupporting

confidence: 67%

“… Comparison of the X‐ray crystal structures of HAL (from Pseudomonas putida )64 and PAL (from Rhodosporidium toruloides )49a with the homology model of PAL (from Petroselinum crispum ):86 a) tetrameric structures; b) single subunits (the catalytically important residues are shown as stick models; moieties containing MIO prosthetic groups are colored green). …”

Section: The Active Sites Of Hal and Palmentioning

confidence: 99%

“… Model of the substrate‐free active site of PAL (from P. crispum )86 superimposed on the active site of HAL (from P. putida )64 The lighter colors (yellow labels; light‐blue, light‐green, and light‐red ribbons) indicate the PAL model; the darker colors (orange labels, blue, green, and red ribbons) indicate the HAL structure. …”

Section: The Active Sites Of Hal and Palmentioning

confidence: 99%

“…N ‐Methyl‐ L ‐phenylalanine, N ‐methyl‐4‐nitro‐ L ‐phenylalanine, and N , N ‐dimethyl‐4‐nitro‐ L ‐phenylalanine were investigated as substrates or inhibitors of PAL from Petroselinum crispum 86. Although N ‐methyl‐ L ‐phenylalanine was a moderate substrate ( K m =6.6 m M , k cat =0.22 s −1 ), no reverse reaction was observed with methylamine and ( E )‐cinnamate.…”

Section: Hal and Pal Inhibitors And Alternative Substratesmentioning

confidence: 99%

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Friedel–Crafts‐Type Mechanism for the Enzymatic Elimination of Ammonia from Histidine and Phenylalanine

2005

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The surprisingly high catalytic activity and selectivity of enzymes stem from their ability to both accelerate the target reaction and suppress competitive reaction pathways that may even be dominant in the absence of enzymes. For example, histidine and phenylalanine ammonia-lyases (HAL and PAL) trigger the abstraction of the nonacidic beta protons of these amino acids while leaving the much more acidic ammonium hydrogen atoms untouched. Both ammonia-lyases have a catalytically important electrophilic group, which was believed to be dehydroalanine for 30 years but has now been revealed by X-ray crystallography and UV spectroscopy to be a highly electrophilic 5-methylene-3,5-dihydroimidazol-4-one (MIO) group. Experiments suggest that the reaction is initiated by the electrophilic attack of MIO on the aromatic ring of the substrate. This incomplete Friedel-Crafts-type reaction leads to the activation of a beta proton and its stereospecific abstraction, followed by the elimination of ammonia and regeneration of the MIO group. The plausibility of such a mechanism is supported by a synthetic model. The application of the PAL reaction in the biocatalytic synthesis of enantiomerically pure alpha-amino beta-aryl propionates from aryl acrylates is also discussed.

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Section: The Active Sites Of Hal and Palsupporting

confidence: 67%

Section: The Active Sites Of Hal and Palmentioning

confidence: 99%

Section: The Active Sites Of Hal and Palmentioning

confidence: 99%

Section: Hal and Pal Inhibitors And Alternative Substratesmentioning

confidence: 99%

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Friedel–Crafts‐Type Mechanism for the Enzymatic Elimination of Ammonia from Histidine and Phenylalanine

2005

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“…The K m for ammonia for the reverse reaction has been determined to be 4.4 m at pH 8.8 and 2.6 m at pH 10. [10] Thus, about 90 % of the possible yields of the d-amino acids were achieved (Table 2). This is the first time that these d-amino acids were prepared by the PAL reaction.…”

Section: Discussionmentioning

confidence: 99%

The Interaction of Heteroaryl‐Acrylates and Alanines with Phenylalanine Ammonia‐Lyase from Parsley

Paizs

Katona

Rétey

2006

Chemistry A European J

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Acrylic acids and alanines substituted with heteroaryl groups at the beta-position were synthesized and spectroscopically characterized (UV, HRMS, (1)H NMR, and (13)C NMR spectroscopy). The heteroaryl groups were furanyl, thiophenyl, benzofuranyl, and benzothiophenyl and contained the alanyl side chains either at the 2- or 3-positions. While the former are good substrates for phenylalanine ammonia-lyase (PAL), the latter compounds are inhibitors. Exceptions are thiophen-3-yl-alanine, a moderate substrate and furan-3-yl-alanine, which is inert. Possible reasons for these exceptions are discussed. Starting from racemic heteroaryl-2-alanines their D-enantiomers were prepared by using a stereodestructive procedure. From the heteroaryl-2-acrylates, the L-enantiomers of the heteroaryl-2-alanines were prepared at high ammonia concentration. These results can be best explained by a Friedel-Crafts-type electrophilic attack at the aromatic part of the substrates as the initial step of the PAL reaction.

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Enzymatische Eliminierung von Ammoniak aus Histidin und Phenylalanin: der Friedel‐Crafts‐ähnliche Mechanismus

Poppe

Rétey

2005

Angewandte Chemie

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Die erstaunlich hohe katalytische Aktivität und Selektivität von Enzymen manifestiert sich einerseits in einer Beschleunigung der Zielreaktion und andererseits in der Unterdrückung alternativer Reaktionswege, die ohne das betreffende Enzym kinetisch kompetitiv oder sogar dominant wären. Histidin‐ und Phenylalanin‐Ammoniak‐Lyasen (HALs und PALs) z. B. bewirken eine Abspaltung des nicht‐aciden β‐Protons dieser Aminosäuren, ohne das weitaus acidere Ammonium‐Proton anzutasten. Beide Ammoniak‐Lyasen enthalten eine katalytisch wichtige elektrophile Gruppe, die während dreißig Jahren für Dehydroalanin gehalten wurde. Die Röntgenkristallstruktur von HAL ließ jedoch eine andere elektrophile Gruppe erkennen, nämlich 5‐Methylen‐3,5‐dihydroimidazol‐4‐on (MIO), die UV‐spektroskopisch auch in PAL nachgewiesen wurde. Kürzlich ermittelte Röntgenkristallstrukturen von PAL aus Rhodosporidium toruloides und Petrosilenum crispum bestätigten das Vorliegen der MIO‐Gruppe. Experimente legen nahe, dass die Reaktion durch einen elektrophilen Angriff von MIO auf den aromatischen Ring des Substrates gestartet wird. Diese Friedel‐Crafts‐ähnliche Reaktion aktiviert das β‐Proton und führt zu seiner stereospezifischen Abspaltung mit nachfolgender Eliminierung von Ammoniak und Regenerierung der MIO‐Gruppe. Die Plausibilität eines solchen Mechanismus wird durch ein synthetisches Modell gestützt. Diskutiert wird außerdem die Anwendung der PAL‐Reaktion in der biokatalytischen Synthese von enantiomerenreinen α‐Amino‐β‐arylpropionaten aus Arylacrylaten.

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Mechanistic Investigation of Phenylalanine Ammonia Lyase by Using N‐Methylated Phenylalanines

Cited by 8 publications

References 32 publications

Friedel–Crafts‐Type Mechanism for the Enzymatic Elimination of Ammonia from Histidine and Phenylalanine

Friedel–Crafts‐Type Mechanism for the Enzymatic Elimination of Ammonia from Histidine and Phenylalanine

The Interaction of Heteroaryl‐Acrylates and Alanines with Phenylalanine Ammonia‐Lyase from Parsley

Enzymatische Eliminierung von Ammoniak aus Histidin und Phenylalanin: der Friedel‐Crafts‐ähnliche Mechanismus

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