scholarly journals Molecular cloning, expression and catalytic activity of a human AKR7 member of the aldo–keto reductase superfamily: evidence that the major 2-carboxybenzaldehyde reductase from human liver is a homologue of rat aflatoxin B1-aldehyde reductase

1998 ◽  
Vol 332 (1) ◽  
pp. 21-34 ◽  
Author(s):  
Linda S. IRELAND ◽  
David J. HARRISON ◽  
Gordon E. NEAL ◽  
John D. HAYES
Keyword(s):  
Aflatoxin B1 ◽  
Human Liver ◽  
Reductase Activity ◽  
Structural Features ◽  
Aldehyde Group ◽  
Succinic Semialdehyde ◽  
Aldehyde Reductase ◽  
Extrahepatic Tissues ◽  
Pharmaceutically Active Compound

The masking of charged amino or carboxy groups by N-phthalidylation and O-phthalidylation has been used to improve the absorption of many drugs, including ampicillin and 5-fluorouracil. Following absorption of such prodrugs, the phthalidyl group is hydrolysed to release 2-carboxybenzaldehyde (2-CBA) and the pharmaceutically active compound; in humans, 2-CBA is further metabolized to 2-hydroxymethylbenzoic acid by reduction of the aldehyde group. In the present work, the enzyme responsible for the reduction of 2-CBA in humans is identified as a homologue of rat aflatoxin B1-aldehyde reductase (rAFAR). This novel human aldo–keto reductase (AKR) has been cloned from a liver cDNA library, and together with the rat protein, establishes the AKR7 family of the AKR superfamily. Unlike its rat homologue, human AFAR (hAFAR) appears to be constitutively expressed in human liver, and is widely expressed in extrahepatic tissues. The deduced human and rat protein sequences share 78% identity and 87% similarity. Although the two AKR7 proteins are predicted to possess distinct secondary structural features which distinguish them from the prototypic AKR1 family of AKRs, the catalytic- and NADPH-binding residues appear to be conserved in both families. Certain of the predicted structural features of the AKR7 family members are shared with the AKR6 β-subunits of voltage-gated K+-channels. In addition to reducing the dialdehydic form of aflatoxin B1-8,9-dihydrodiol, hAFAR shows high affinity for the γ-aminobutyric acid metabolite succinic semialdehyde (SSA) which is structurally related to 2-CBA, suggesting that hAFAR could function as both a SSA reductase and a 2-CBA reductase in vivo. This hypothesis is supported in part by the finding that the major peak of 2-CBA reductase activity in human liver co-purifies with hAFAR protein. The cDNA sequence for human AFAR has been assigned by GenBank the accession number AF026947.

scholarly journals Purification from rat liver of a novel constitutively expressed member of the aldo-keto reductase 7 family that is widely distributed in extrahepatic tissues

2000 ◽  
Vol 348 (2) ◽  
pp. 389-400 ◽  
Author(s):  
Vincent P. KELLY ◽  
Linda S. IRELAND ◽  
Elizabeth M. ELLIS ◽  
John D. HAYES
Keyword(s):  
Rat Liver ◽  
Aflatoxin B1 ◽  
Single Gene ◽  
Reversed Phase ◽  
Cross Reactivity ◽  
Rat Tissues ◽  
Succinic Semialdehyde ◽  
Aldehyde Reductase ◽  
Cibacron Blue ◽  
Sds Page

Antiserum raised against human aflatoxin B1 aldehyde reductase 1 (hAFAR1) has been used to identify a previously unrecognized rat aldo-keto reductase (AKR). This novel enzyme is designated rat aflatoxin B1 aldehyde reductase 2 (rAFAR2) and it characteristically migrates faster during SDS/PAGE than does the archetypal ethoxyquin-inducible rAFAR protein (now called rAFAR1). Significantly, rAFAR2 is essentially unreactive with polyclonal antibodies raised against rAFAR1. Besides its distinct electrophoretic and immunochemical properties, rAFAR2 appears to be regulated differently from rAFAR1 as it is expressed in most rat tissues and does not appear to be induced by ethoxyquin. Multiple forms of rAFAR2 have been identified. Anion-exchange chromatography on Q-Sepharose, followed by adsorption chromatography on columns of Matrex Orange A and Cibacron Blue, have been employed to purify rAFAR2 from rat liver cytosol. The Q-Sepharose chromatography step resulted in the resolution of rAFAR2 into three peaks of AKR activity, two of which were purified and shown to be capable of catalysing the reduction of 2-carboxybenzaldehyde, succinic semialdehyde, 4-nitrobenzaldehyde and 9,10-phenathrenequinone. The two most highly purified rAFAR2-containing preparations eluted from the Cibacron Blue column were 91 and 98% homogeneous. Analysis of these by SDS/PAGE indicated that the least anionic (peak CBA5) comprised a polypeptide of 37.0 kDa, whereas the most anionic (peak CBA6) contained two closely migrating polypeptides of 36.8 and 37.0 kDa; by contrast, in the present study, rAFAR1 was estimated by SDS/PAGE to be composed of 38.0 kDa subunits. Final purification of the 37 kDa polypeptide in CBA5 and CBA6 was accomplished by reversed-phase HPLC. Partial proteolysis of the two preparations of the 37 kDa polypeptide with Staphylococcus aureus V8 protease yielded fragments of identical size, suggesting that they represent the product of a single gene. Furthermore, the peptide maps from CBA5 and CBA6 differed substantially from that yielded by rAFAR1, indicating that they are genetically distinct from the inducible reductase. A peptide generated by CNBr digestion of the 37 kDa polypeptide from CBA6 was shown by Edman degradation to share 88% sequence identity with residues Tyr168-Leu183 of rAFAR1. This provides evidence that the rat protein identified by its cross-reactivity with anti-hAFAR1 serum is an additional member of the AKR7 family.

scholarly journals Substrate specificity of an aflatoxin-metabolizing aldehyde reductase

1995 ◽  
Vol 312 (2) ◽  
pp. 535-541 ◽  
Author(s):  
E M Ellis ◽  
J D Hayes
Keyword(s):  
Substrate Specificity ◽  
High Activity ◽  
Rat Liver ◽  
Aflatoxin B1 ◽  
Succinic Semialdehyde ◽  
Aldehyde Reductase ◽  
Aliphatic Aldehydes ◽  
Alpha Beta ◽  
Low Activity

The enzyme from rat liver that reduces aflatoxin B1-dialdehyde exhibits a unique catalytic specificity distinct from that of other aldo-keto reductases. This enzyme, designated AFAR, displays high activity towards dicarbonyl-containing compounds with ketone groups on adjacent carbon atoms; 9,10-phenanthrenequinone, acenaphthenequinone and camphorquinone were found to be good substrates. Although AFAR can also reduce aromatic and aliphatic aldehydes such as succinic semialdehyde, it is inactive with glucose, galactose and xylose. The enzyme also exhibits low activity towards alpha, beta-unsaturated carbonyl-containing compounds. Determination of the apparent Km reveals that AFAR has highest affinity for 9,10-phenanthrenequinone and succinic semialdehyde, and low affinity for glyoxal and DL-glyceraldehyde.

Proton MR Spectroscopic Features of the Human Liver: In-Vivo Application to the Normal Condition

1999 ◽  
Vol 40 (1) ◽  
pp. 77
Author(s):  
Soon Gu Cho ◽  
Mi Young Kim ◽  
Young Soo Kim ◽  
Won Choi ◽  
Seok Hwan Shin ◽  
...  
Keyword(s):  
Normal Condition ◽  
Human Liver

Traceable Peptidic Ligands that Target Ghrelin Receptors

2020 ◽  
Vol 21 (10) ◽  
pp. 955-964 ◽  
Author(s):  
Mengjie Liu ◽  
John Wade ◽  
Mohammed Akhter Hossain
Keyword(s):  
In Vivo Imaging ◽  
Peptide Hormone ◽  
Structural Features ◽  
Pharmacological Properties ◽  
Imaging Studies ◽  
Cognate Receptor ◽  
Ghrelin Receptors ◽  
Biochemical Research

: Ghrelin is a 28-amino acid octanoylated peptide hormone that is implicated in many physiological and pathophysiological processes. Specific visualization of ghrelin and its cognate receptor using traceable ligands is crucial in elucidating the localization, functions, and expression pattern of the peptide’s signaling pathway. Here 12 representative radio- and fluorescently-labeled peptide-based ligands are reviewed for in vitro and in vivo imaging studies. In particular, the focus is on their structural features, pharmacological properties, and applications in further biochemical research.

Promising Anti-stroke Signature of Voglibose: Investigation through In- Silico Molecular Docking and Virtual Screening in In-Vivo Animal Studies

2020 ◽  
Vol 20 (3) ◽  
pp. 223-235
Author(s):  
Pooja Shah ◽  
Vishal Chavda ◽  
Snehal Patel ◽  
Shraddha Bhadada ◽  
Ghulam Md. Ashraf
Keyword(s):  
Molecular Docking ◽  
Virtual Screening ◽  
In Silico ◽  
Reductase Activity ◽  
Infarct Volume ◽  
Docking Studies ◽  
Serum Glucose ◽  
In Vivo Studies ◽  
In Silico Molecular Docking

Background: Postprandial hyperglycemia considered to be a major risk factor for cerebrovascular complications. Objective: The current study was designed to elucidate the beneficial role of voglibose via in-silico in vitro to in-vivo studies in improving the postprandial glycaemic state by protection against strokeprone type 2 diabetes. Material and Methods: In-Silico molecular docking and virtual screening were carried out with the help of iGEMDOCK+ Pymol+docking software and Protein Drug Bank database (PDB). Based on the results of docking studies, in-vivo investigation was carried out for possible neuroprotective action. T2DM was induced by a single injection of streptozotocin (90mg/kg, i.v.) to neonates. Six weeks after induction, voglibose was administered at the dose of 10mg/kg p.o. for two weeks. After eight weeks, diabetic rats were subjected to middle cerebral artery occlusion, and after 72 hours of surgery, neurological deficits were determined. The blood was collected for the determination of serum glucose, CK-MB, LDH and lipid levels. Brains were excised for determination of brain infarct volume, brain hemisphere weight difference, Na+-K+ ATPase activity, ROS parameters, NO levels, and aldose reductase activity. Results: In-silico docking studies showed good docking binding score for stroke associated proteins, which possibly hypotheses neuroprotective action of voglibose in stroke. In the present in-vivo study, pre-treatment with voglibose showed a significant decrease (p<0.05) in serum glucose and lipid levels. Voglibose has shown significant (p<0.05) reduction in neurological score, brain infarct volume, the difference in brain hemisphere weight. On biochemical evaluation, treatment with voglibose produced significant (p<0.05) decrease in CK-MB, LDH, and NO levels in blood and reduction in Na+-K+ ATPase, oxidative stress, and aldose reductase activity in brain homogenate. Conclusion: In-silico molecular docking and virtual screening studies and in-vivo studies in MCAo induced stroke, animal model outcomes support the strong anti-stroke signature for possible neuroprotective therapeutics.

Polyamines and Related Nitrogen Compounds in the Chemotherapy of Neglected Diseases Caused by Kinetoplastids

2018 ◽  
Vol 18 (5) ◽  
pp. 321-368 ◽  
Author(s):  
Juan A. Bisceglia ◽  
Maria C. Mollo ◽  
Nadia Gruber ◽  
Liliana R. Orelli
Keyword(s):  
Drug Targets ◽  
Redox Homeostasis ◽  
Cost Effective ◽  
Structural Features ◽  
Mammalian Host ◽  
Neglected Diseases ◽  
Nitrogen Compounds ◽  
Chemical Structures

Neglected diseases due to the parasitic protozoa Leishmania and Trypanosoma (kinetoplastids) affect millions of people worldwide, and the lack of suitable treatments has promoted an ongoing drug discovery effort to identify novel nontoxic and cost-effective chemotherapies. Polyamines are ubiquitous small organic molecules that play key roles in kinetoplastid parasites metabolism, redox homeostasis and in the normal progression of cell cycles, which differ from those found in the mammalian host. These features make polyamines attractive in terms of antiparasitic drug development. The present work provides a comprehensive insight on the use of polyamine derivatives and related nitrogen compounds in the chemotherapy of kinetoplastid diseases. The amount of literature on this subject is considerable, and a classification considering drug targets and chemical structures were made. Polyamines, aminoalcohols and basic heterocycles designed to target the relevant parasitic enzyme trypanothione reductase are discussed in the first section, followed by compounds directed to less common targets, like parasite SOD and the aminopurine P2 transporter. Finally, the third section comprises nitrogen compounds structurally derived from antimalaric agents. References on the chemical synthesis of the selected compounds are reported together with their in vivo and/or in vitro IC50 values, and structureactivity relationships within each group are analyzed. Some favourable structural features were identified from the SAR analyses comprising protonable sites, hydrophobic groups and optimum distances between them. The importance of certain pharmacophoric groups or amino acid residues in the bioactivity of polyamine derived compounds is also discussed.

scholarly journals Interaction of Lactoferrin with Unsaturated Fatty Acids: In Vitro and In Vivo Study of Human Lactoferrin/Oleic Acid Complex Cytotoxicity

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1602
Author(s):  
Anna Elizarova ◽  
Alexey Sokolov ◽  
Valeria Kostevich ◽  
Ekaterina Kisseleva ◽  
Evgeny Zelenskiy ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Structural Changes ◽  
Unsaturated Fatty Acids ◽  
Structural Features ◽  
Control Group ◽  
Acid Complex ◽  
Hepatoma 22A ◽  
Constitutive Parameters

As shown recently, oleic acid (OA) in complex with lactoferrin (LF) causes the death of cancer cells, but no mechanism(s) of that toxicity have been disclosed. In this study, constitutive parameters of the antitumor effect of LF/OA complex were explored. Complex LF/OA was prepared by titrating recombinant human LF with OA. Spectral analysis was used to assess possible structural changes of LF within its complex with OA. Structural features of apo-LF did not change within the complex LF:OA = 1:8, which was toxic for hepatoma 22a cells. Cytotoxicity of the complex LF:OA = 1:8 was tested in cultured hepatoma 22a cells and in fresh erythrocytes. Its anticancer activity was tested in mice carrying hepatoma 22a. In mice injected daily with LF-8OA, the same tumor grew significantly slower. In 20% of animals, the tumors completely resolved. LF alone was less efficient, i.e., the tumor growth index was 0.14 for LF-8OA and 0.63 for LF as compared with 1.0 in the control animals. The results of testing from 48 days after the tumor inoculation showed that the survival rate among LF-8OA-treated animals was 70%, contrary to 0% rate in the control group and among the LF-treated mice. Our data allow us to regard the complex of LF and OA as a promising tool for cancer treatment.

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