Archives

  • 2018-07
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-07
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • 2024-04

    • br Materials and methods br Results br Discussion

    2023-02-06


    Materials and methods
    Results
    Discussion
    Competing financial interests
    Acknowledgements The work was partially supported by grants from the National Natural Science Foundation of China (Grant no. 31530053 and 31401424) and National Science and Technology Support Plan (Grant no. 2013BAD01B03).
    Introduction Aldehyde dehydrogenases (ALDHs) (aldehyde: NAD(P)+ oxidoreductases, EC 1.2.1.3) are group of ubiquitously distributed multigenic family of nicotinamide adenine dinucleotide phosphate [NAD(P)+]-dependent isoenzymes that catalyze the irreversible oxidation of a broad spectrum of aliphatic and aromatic aldehydes to their corresponding innocuous carboxylic Methoxyresorufin australia [1]. The enzymes manifest functional polymorphism and have broad substrate specificity with tissue-specific distribution [2], [3], [4], [5]. The high cellular NAD(P)+/NAD(P)H ratio makes the ALDH system an efficient process for detoxifying unwanted aldehydes from cells [6]. They are involved in cellular response to oxidative stress and detoxification of stress generated aldehydes [7] also possessed esterase activity [8]. ALDHs have multifaceted role that are physiologically and toxicologically relevant −they modulate cell proliferation, differentiation and survival and support cellular homeostasis [4], [9]. ALDH expression has been established to be a possibly relevant prognostic marker and has also been implicated in several cancerous cells [3], [4]; in myocardial ischemia [10], in Alzheimer’s and Parkinson’s diseases [11], Sjorgren-Larsson syndrome [12] and alcohols-related pathology [13]. Cytosolic ALDHs are tetrameric with subunit molecular weight of 50–55kDa [14], [15]. The kinetic mechanism followed a 2-step, ordered bi bi steady state sequential mechanism, with initial binding of NAD(P)+ before aldehydic substrate and NAD(P)H dissociating last [16], [17]. ALDH displayed conformational flexibility within the active site and cofactor dynamics for an efficient catalysis [8]. Recent works have shown that ALDHs have other crucial functions in addition to its primary detoxification mechanism. It is the non-catalytic binding properties for endobiotics and exobiotics [9], [18]. This is connected to sequestration of toxicants. Ferulic acid (m-methoxy- p-hydroxycinnamic acid; FA) (Fig. 1) is a phenolic phytochemical of the cinnamate family found in fruits and vegetables [19]. FA is a strong dibasic acid having carboxylate and phenolate anion with three unique functional groups- 3-methoxyl and 4-hyroxyl of benzene ring, the carboxylate group and the adjacent unsaturated CC double bond [20] with pKa of 4.58. FA and its derivatives exhibit a wide range of important biological [21] and therapeutic properties [22]. Ferulic acid has neuroprotective, anti-inflammatory, antibacterial, antidiabetic, anticarcinogenic, antiageing, UV-protective and radio-protective effects, which can be attributed to its effectual and efficient antioxidant capacity [22], [23]. The antioxidant property of FA is connected to its electron phenolic nucleus and resonance forming unsaturated side chain [20], [24]. The anions have a high degree of resonance stabilization, which increases its acidity in comparison with similar phenolic acids [25]. The biological and pharmacological benefits of FA is linked to these [20]. The multifaceted therapeutic potential of ferulic acid and its derivatives been aptly captured earlier [20]. It has been reported to be beneficial in Alzheimer’s disease [26] and cancer therapeutics [27]. Aldehyde dehydrogenase (ALDH) activity has been implicated in ferulic acid synthetic pathway that is responsible for lignin synthesis and consequently plant cell wall strength [28], [29] and aluminum stress management [7]. ALDH up-regulation has the potential to perform multiple functions within the cell [7]. Increased aldehyde dehydrogenase activity (ALDH) has been demonstrated to be a mechanism of antitumor drug resistance [4]. Therefore, an ALDH specific, competitive type (reversible) inhibitor not requiring enzymatic activation would be preferred for in vivo inhibition of ALDH. ALDH can be a major ferulic acid-binding protein and could be a good candidate in binding of ALDH up-regulated patho​phys​i​o​log​i​cally associated diseases. However, the affinity and interaction mechanisms of ferulic acid to ALDH still remain uncharted. The impact and consequence of ALDH-FA derivatives are unknown; also the energetics of the binding not yet being elucidated. Fluorescence spectroscopy techniques is one of the most accessible method to monitor the binding of small organic molecules to proteins because of its high sensitivity, accuracy, rapidity, convenience in performance and simplicity [30], [31]. In this paper, the binding of ferulic acid to ALDH was studied under physiological condition (pH 7.4), condition near the pKa of ferulic acid and condition at the optimum pH of ALDH by spectroscopic techniques. The binding constants were calculated and binding mechanism was proposed. In addition the effect of ferulic acid on the conformation of ALDH was also studied. It is hoped that this work will provide more than just useful information on the binding mechansim at molecular level.