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The correlation in the increase of BADH mRNA protein
The correlation in the increase of BADH mRNA, protein levels, and enzyme activity, demonstrate that oxidation of betaine aldehyde by BADH is primordial to regulate the GB accumulation during physiological cardiac hypertrophy induced by pregnancy, this implies a major role because GB levels enhance cell volume regulation to protect ventricular myocytes, reduces the homocysteine levels and triggers gene regulation [25], [26], [27]. Besides, previous results in our laboratory demonstrate that physiological cardiac hypertrophy induced by pregnancy involves a shift in the cellular metabolism, up-regulation of target genes in the energy metabolism, and increased demand in the β-oxidation of lipids rather than glucose metabolism [28]. Considering the broad substrate specificity of BADH in rats, with a high affinity for γ-trimethylaminobutyraldehyde substrate, the role of BADH should be considered in other mechanisms, like carnitine biosynthesis and regulation. Further investigations are required to completely understand the BADH role in the 73122 to physiological cardiac hypertrophy induced by pregnancy.
Conflict of interest
Acknowledgments
This study was funded by the Universidad de Sonora project No. USO513002776. Special thanks to the students of the Laboratorio Ciencias de la Salud for their continual support and enthusiasm during this project.
Introduction
Human saliva contains many antioxidant enzymes such as catalase, superoxide dismutase, peroxidase, aldehyde dehydrogenase (ALDH), etc.[1], [2], [3], [4]. Human salivary ALDH (hsALDH) primarily consists of one isozyme characterized as ALDH3A1 (EC 1.2.1.5) [5], [6], [7], [8], [9]. ALDH3A1 is a homodimeric enzyme consisting of 54kDa subunits [5], [7], [10], [11]. HsALDH catalyzes the oxidation of aromatic and long chain aliphatic aldehydes to their corresponding acids [7], [10], [12]. It also catalyzes the hydrolysis of ester bonds [13], [14]. The enzyme utilizes either NAD+ or NADP+ as cofactor for catalyzing the oxidation reactions [7], [15], [16]. The active site of the enzyme contains a cysteine residue which is involved in substrate binding and catalysis [17]. The cysteine residue in its reduced form takes part in the catalytic reaction but is readily air oxidized. This is prevented in vitro by adding dithiothreitol (DTT) or glutathione (GSH) to the enzyme solution [5], [18].
HsALDH appears to be the first line of defence against toxic aldehydes contained in exogenous sources such as foods, drugs, contaminants, etc.[12], [19], [20], [21]. The activity of this enzyme is important for maintaining healthy oral cavity and protection from oral cancer. Lower activity of hsALDH has been found to be a risk factor for the development of oral cancer [22]. Ingestion of large quantities of coffee or broccoli increases the level of this enzyme in the saliva [9]. Sulforaphane from broccoli was recently found to activate the enzyme in vitro[23]. This isozyme (ALDH3) has also been found to be involved in the chemoresistance of certain types of cancers as it catalyzes the oxidation of the chemotherapeutic drugs such as oxazaphosphorine and cyclophosphamide [11], [24], [25], [26], [27], [28], [29]. ALDH3A1 is also expressed in other organs and tissues such as the stomach, hair roots, cornea, liver and lungs [6], [7], [30], [31], [32]. Apart from detoxification, ALDH3A1 is involved in other physiological functions such as cell proliferation, protection from UV radiation and oxidative damage in the cornea, etc.[31], [33]. This enzyme is over expressed in many types of cancers such as those of the breast, oral cavity, pancrease, etc.[8], [11], [34], [35]. It is also over expressed in the cancer stem cells and therefore, it has been utilized as a marker for cancer stem cells [36], [37].
Most studies on hsALDH have been done on the crude enzyme. In the present study, the activity and stability of purified hsALDH has been determined under different conditions such as temperature, in presence of denaturants [Urea and guanidine hydrochloride (GnHCl) and in the presence of salt (NaCl). Determination of storage and operational stability of the pure enzyme is important for its in vitro use in research and in therapeutic applications.