Stereospecificity of cinnamyl alcohol dehydrogenase and synthesis of stereospecifically labelled coniferyl alcohol

Using horse liver alcohol dehydrogenase, stereospecifically tritiated (R)- and (S)-(γ-3H)-coniferyl alcohol was synthesized. Using both of these substrates it was demonstrated that cinnamyl alcohol dehydrogenase from lignifying Forsythia tissue specifically removes the pro-R-hydrogen atom of coniferyl alcohol in the oxidation to the aldehyde. This also means that in the reverse reaction the A-hydrogen of NADPH is transferred to the Re-site of coniferyl aldehyde

Sheep liver cytosolic aldehyde dehydrogenase : a fresh perspective : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey University, New Zealand

The pre-steady-state mechanism of aldehyde dehydrogenase has been further investigated using synthesised deuterated 4-trans-(N,N-dimethylamino) cinnamaldehyde as a substrate. Reporter groups of the active site of ALDH have indicated the presence of a divalent or trivalent metal electrophile, shown in chapter 3 as being either Fe (II) or Fe (III) . Studies of the spectral properties of NADH bound to aldehyde dehydrogenase have revealed the presence of at least two spectrally different enzyme-NADH species. The consequences of this information are important in interpretation of the kinetic data and understanding apparently contradictory experimental results from different research workers. The steady-state kinetics of ALDH have been further investigated. A sensitive substrate for use in enzyme immunoassays has been designed and synthesised. The preliminary kinetic behaviour observed using this substrate has been studied with three enzymes. Aldehyde dehydrogenase has been used as a model system for studying the effects of electromagnetic radiation on biological systems

Effect of Elaeagnus Conferta Roxb (Elaeagnaceae) Dry Fruit on the Activities of Hepatic Alcohol Dehydrogenase and Aldehyde Dehydrogenase in Mice

Purposes: To determine the effect of Elaeagnus conferta Roxb dry fruit powder (ECR) on blood alcohol clearance and on the activities of hepatic alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH).Methods: In a randomized controlled study, acute alcohol intoxication was induced in mice with Hongxing liquor containing 65 % v/v ethanol orally. The effect of ECR on blood alcohol clearance and on the activities of hepatic alcohol dehydrogenase and aldehyde dehydrogenase in the mice was then investigated.Results: A 30-min pretreatment with ECR at 400 and 800 mg/kg led to a faster clearance of blood alcohol after the alcohol ingestion. The concentration of blood alcohol at 4 h after alcohol ingestion decreased by 21.2 % in mice pretreated with 800 mg/kg ECR. The activities of hepatic alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) were enhanced by ECR.Conclusion: These results suggest that pretreatment with ECR might stimulate the clearance of blood alcohol by increasing the activities of hepatic alcohol dehydrogenase and aldehyde dehydrogenase.Keywords: Elaeagnus conferta Roxb, blood alcohol clearance, alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH)

Aldehyde dehydrogenase 3A1 promotes multi-modality resistance and alters gene expression profile in human breast adenocarcinoma MCF-7 cells

Aldehyde dehydrogenases participate in a variety of cellular homeostatic mechanisms like metabolism, proliferation, differentiation, apoptosis, whereas recently, they have been implicated in normal and cancer cell stemness. We explored roles for ALDH3A1 in conferring resistance to chemotherapeutics/radiation/oxidative stress and whether ectopic overexpression of ALDH3A1 could lead to alterations of gene expression profile associated with cancer stem cell-like phenotype. MCF-7 cells were stably transfected either with an empty vector (mock) or human aldehyde dehydrogenase 3A1 cDNA. The expression of aldehyde dehydrogenase 3A1 in MCF-7 cells was associated with altered cell proliferation rate and enhanced cell resistance against various chemotherapeutic drugs (4-hydroxyperoxycyclophosphamide, doxorubicin, etoposide, and 5-fluorouracil). Aldehyde dehydrogenase 3A1 expression also led to increased tolerance of MCF-7 cells to gamma radiation and hydrogen peroxide-induced stress. Furthermore, aldehyde dehydrogenase 3A1-expressing MCF-7 cells exhibited gene up-regulation of cyclins A, B1, B2, and down-regulation of cyclin D1 as well as transcription factors p21, CXR4, Notch1, SOX2, SOX4, OCT4, and JAG1. When compared to mock cells, no changes were observed in mRNA levels of ABCA2 and ABCB1 protein pumps with only a minor decrease of the ABCG2 pump in the aldehyde dehydrogenase 3A1-expressing cells. Also, the adhesion molecules EpCAM and CD49F were also found to be up-regulated in aldehyde dehydrogenase 3A1expressing cells. Taken together, ALDH3A1 confers a multi-modality resistance phenotype in MCF-7 cells associated with slower growth rate, increased clonogenic capacity, and altered gene expression profile, underlining its significance in cell homeostasis

On the role of microsomal aldehyde dehydrogenase in metabolism of aldehydic products of lipid peroxidation

AbstractTo elucidate a possible role of membrane-bound aldehyde dehydrogenase in the detoxication of aldehydic products of lipd peroxidation, the substrate specificity of the highly purified microsomal enzyme was investigated. The aldehyde dehydrogenase was active with different aliphatic aldehydes including 4-hydroxyalkenals, but did not react with malonic dialdehyde. When Fe/ADP-ascorbate-induced lipid peroxidation of arachidonic acid was carried out in an in vitro system, the formation of products which react with microsomal aldehyde dehydrogenase was observed parallel with malonic dialdehyde accumulation

Expression of aldehyde dehydrogenase after neoadjuvant chemotherapy is associated with expression of hypoxia-inducible factors 1 and 2 alpha and predicts prognosis in locally advanced breast cancer

OBJECTIVE: To analyze the expression of hypoxia-inducible factors (hypoxia-inducible factor 1A and hypoxia-inducible factor 2A) and aldehyde dehydrogenase proteins in patients with locally advanced breast carcinoma who were subjected to neoadjuvant chemotherapy. METHODS: We included 90 patients with histologically confirmed stage II and III breast carcinoma who were treated with neoadjuvant chemotherapy between 2000 and 2005. Immunohistochemistry for aldehyde dehydrogenase, hypoxia-inducible factor 1A, and hypoxia-inducible factor 2A was performed before and after neoadjuvant chemotherapy. We analyzed the influence of clinical and pathological features on clinical and pathological response, disease-free survival, and overall survival. RESULTS: An objective clinical response to neoadjuvant chemotherapy was observed in 80% of patients, with 12% showing a complete pathological response. Among all clinical and pathological parameters, only the expression of hypoxia-inducible factor 1A was associated with a pathological response. A positive association was found between expression of aldehyde dehydrogenase and that of hypoxia-inducible factor 1A before and after chemotherapy. Aldehyde dehydrogenase expression was associated with expression of hypoxia inducible-factor 2A in tumors after neoadjuvant treatment. In a univariate analysis, prognosis was influenced by age, pathological response, metastasis to axillary lymph nodes after neoadjuvant chemotherapy, overexpression of hypoxia-inducible factor 2, and the presence of aldehyde dehydrogenase-positive cells within the primary tumor after neoadjuvant chemotherapy. In a multivariate analysis, only age and the presence of aldehyde dehydrogenase-positive cells after chemotherapy were associated with reduced overall survival. CONCLUSION: The presence of aldehyde dehydrogenase-positive cells within the residual tumor after neoadjuvant chemotherapy is associated with an increase in the expression of hypoxia-inducible factor 2A and with poor prognosis in patients with locally advanced breast cancer

Aldehyde dehydrogenase 1A1 and gelsolin identified as novel invasion-modulating factors in conditioned medium of pancreatic cancer cells

Conditioned medium (CM) from clonal sub-populations of the pancreatic cancer cell line, MiaPaCa-2 with differing invasive abilities, were examined for their effect on in vitro invasion. Conditioned medium from Clone #3 (CM#3) strongly promoted invasion, while CM from Clone #8 (CM#8) inhibited invasion in vitro. 2D DIGE followed by MALDI-TOF MS analysis of CM#3 and CM#8 identified 41 proteins which were differentially regulated; 27 proteins were down-regulated and 14 proteins up-regulated in the invasion-promoting CM#3 when compared to CM#8. Western blotting analysis confirmed the down-regulated expression of gelsolin and the up-regulation of aldehyde dehydrogenase 1A1 in CM#3. Down-regulation of aldehyde dehydrogenase 1A1 in Clone #3 CM and gelsolin levels in Clone #8 CM by siRNA transfection revealed an important involvement of these proteins in promoting and inhibiting invasion in these pancreatic cancer cell lines

Site directed mutagenesis and purification of the cDNA for human class I aldehyde dehydrogenase : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science at Massey University

Aldehyde dehydrogenase (ALDH) is a key enzyme of alcohol metabolism, removing acetaldehyde which is formed as a product of the alcohol dehydrogenase reaction. If acetaldehyde is not effectively removed, acetaldehyde accumulates and produces an adverse reaction to alcohol, with nausea, flushing and increased heart rate and blood pressure. ALDH is involved in the conversion of retinal to retinoic acid (RA). RA has recently been shown to bind to receptors, which then act as nuclear transcription factors and play important roles in foetal development and maintenance of the epithelial layer in the body. Interference by ethanol and perhaps by acetaldehyde with this process is probably the cause of Foetal Alcohol Syndrome. In addition ALDH is also involved in the metabolism of catecholamine neurotransmitters, plays a role in the removal of toxic substances from the body and may have a role in protection against some chemical carcinogens. Dr. Kerrie Jones had obtained moderate levels of expression of recombinant ALDH in E. coli and constructed a number of mutants chosen on the basis of chemical modification data and sequence alignment. Mutant proteins were also expressed and assayed for enzyme activity in crude extracts. The aim of this thesis was to improve purification and yield of the expressed ALDH proteins. By the use of site-directed mutagenesis I attempted to mutate the amino acid residue Lys272 to either alanine, histidine or arginine. Future comparison of the properties of the site-directed mutants with those of the wild type enzyme will help to determine the importance of the residue (which has been replaced by mutagenesis) to catalysis

Role of aldehyde dehydrogenase in hypoxic vasodilator effects of nitrite in rats and humans

Hypoxic conditions favour the reduction of nitrite to nitric oxide (NO) to elicit vasodilatation, but the mechanism(s) responsible for bioconversion remains ill defined. In the present study, we assess the role of aldehyde dehydrogenase 2 (ALDH2) in nitrite bioactivation under normoxia and hypoxia in the rat and human vasculature

Human liver mitochondrial aldehyde dehydrogenase: a C-terminal segment positions and defines the structure corresponding to the one reported to differ in the Oriental enzyme variant

AbstractA C-terminal segment of mitochondrial human liver aldehyde dehydrogenase was characterized. The results prove that a central part of this segment largely but not completely agrees with a structure of a tryptic peptide previously reported for the same isoenzyme. This part corresponds to a segment that contains the exchanged residue in the functionally deficient Oriental variant of mitochondrial aldehyde dehydrogenase [(1984) Proc. Natl. Acad. Sci. USA 81, 258-261]. The data suggest important functions for the C-terminal region of aldehyde dehydrogenase, clarify previously inconsistent results, and establish this structure in the typical enzyme, including the position corresponding to the mutation in the functional variant.Mitochondrial isoenzymeAmino acid sequenceIsoenzyme differenceStructure-function relationshi