The monoclonal antibody Ca37, developed against Candida albicans alcohol dehydrogenase, inhibits the yeast in vitro and in vivo

Candida albicans is a commensal yeast able to cause life threatening invasive infections particularly in immunocompromised patients. Despite the availability of antifungal treatments, mortality rates are still unacceptably high and drug resistance is increasing. We, therefore, generated the Ca37 monoclonal antibody against the C. albicans alcohol dehydrogenase (Adh) 1. Our data showed that Ca37 was able to detect C. albicans cells, and it bound to Adh1 in yeast and Adh2 in hyphae among the cell wall-associated proteins. Moreover, Ca37 was able to inhibit candidal growth following 18 h incubation time and reduced the minimal inhibitory concentration of amphotericin B or fluconazole when used in combination with those antifungals. In addition, the antibody prolonged the survival of C. albicans infected-Galleria mellonella larvae, when C. albicans was exposed to antibody prior to inoculating G. mellonella or by direct application as a therapeutic agent on infected larvae. In conclusion, the Ca37 monoclonal antibody proved to be effective against C. albicans, both in vitro and in vivo, and to act together with antifungal drugs, suggesting Adh proteins could be interesting therapeutic targets against this pathogen.

Alcohol Dehydrogenase: An Autoantibody Target in Patients with Alcoholic Liver Disease

The link between alcohol consumption and liver disease is not direct and several factors including autoimmunity to hepatocyte components have been implicated. We have previously identified alcohol dehydrogenase (ADH) as an autoantigen in autoimmune liver disease and in a proportion of patients with alcoholic liver disease. The aim of the present study is to investigate the association between the presence of anti-ADH antibodies, alcohol consumption and severity of liver damage in alcoholic patients. The presence of antibodies to human ADH β2 and horse ADH was investigated in 108 patients with documented history of alcohol consumption and alcohol related liver disease, 86 being active alcohol abusers and 22 on sustained alcohol withdrawal, 39 with non-alcohol related disease and 22 normal subjects.

Antibodies to either ADH form were more frequently detected in active alcohol abusers (55/86, 64%) than in patients on sustained alcohol withdrawal longer than 6 months (1/8, 13%, p<0.005), HBV infection (2/8, 25%, P=0.03), non-alcohol related disease (9/29, 23%, p<0.0001) and in normal controls (3/22, 14%, p<0.0001); were more frequent in patients with cirrhosis than in those with steatosis (26/34, 76% vs 34/64, 53%, P=0.02); and were associated with elevated levels of ALT (anti-ADH β2, p<0.05), immunoglobulin A (p<0.05) and γ-glutamyl transpeptidase (P=0.01). Anti-ADH antibody positive serum samples were able to inhibit the enzymatic activity of ADH. These findings suggest that anti-ADH antibodies may be triggered by alcohol consumption and act as a disease activity marker in alcoholic liver disease.

Oxidation by neutrophils-derived HOCl increases immunogenicity of proteins by converting them into ligands of several endocytic receptors involved in antigen uptake by dendritic cells and macrophages

The initiation of adaptive immune responses to protein antigens has to be preceded by their uptake by antigen presenting cells and intracellular proteolytic processing. Paradoxically, endocytic receptors involved in antigen uptake do not bind the majority of proteins, which may be the main reason why purified proteins stimulate at most weak immune responses. A shared feature of different types of adjuvants, capable of boosting immunogenicity of protein vaccines, is their ability to induce acute inflammation, characterized by early influx of activated neutrophils. Neutrophils are also rapidly recruited to sites of tissue injury or infection. These cells are the source of potent oxidants, including hypochlorous acid (HOCl), causing oxidation of proteins present in inflammatory foci. We demonstrate that oxidation of proteins by endogenous, neutrophils-derived HOCl increases their immunogenicity. Upon oxidation, different, randomly chosen simple proteins (yeast alcohol dehydrogenase, human and bovine serum albumin) and glycoproteins (human apo-transferrin, ovalbumin) gain the ability to bind with high affinity to several endocytic receptors on antigen presenting cells, which seems to be the major mechanism of their increased immunogenicity. The mannose receptor (CD206), scavenger receptors A (CD204) and CD36 were responsible for the uptake and presentation of HOCl-modified proteins by murine dendritic cells and macrophages. Other scavenger receptors, SREC-I and LOX-1, as well as RAGE were also able to bind HOCl-modified proteins, but they did not contribute significantly to these ligands uptake by dendritic cells because they were either not expressed or exhibited preference for more heavily oxidised proteins. Our results indicate that oxidation by neutrophils-derived HOCl may be a physiological mechanism of conferring immunogenicity on proteins which in their native forms do not bind to endocytic receptors. This mechanism might enable the immune system to detect infections caused by pathogens not recognized by pattern recognition receptors.

Identification of B cell epitopes of alcohol dehydrogenase allergen of Curvularia lunata

Background/Objective

Epitope identification assists in developing molecules for clinical applications and is useful in defining molecular features of allergens for understanding structure/function relationship. The present study was aimed to identify the B cell epitopes of alcohol dehydrogenase (ADH) allergen from Curvularia lunata using in-silico methods and immunoassay.

Method

B cell epitopes of ADH were predicted by sequence and structure based methods and protein-protein interaction tools while T cell epitopes by inhibitory concentration and binding score methods. The epitopes were superimposed on a three dimensional model of ADH generated by homology modeling and analyzed for antigenic characteristics. Peptides corresponding to predicted epitopes were synthesized and immunoreactivity assessed by ELISA using individual and pooled patients' sera.

Result

The homology model showed GroES like catalytic domain joined to Rossmann superfamily domain by an alpha helix. Stereochemical quality was confirmed by Procheck which showed 90% residues in most favorable region of Ramachandran plot while Errat gave a quality score of 92.733%. Six B cell (P1–P6) and four T cell (P7–P10) epitopes were predicted by a combination of methods. Peptide P2 (epitope P2) showed E(X)₂GGP(X)₃KKI conserved pattern among allergens of pathogenesis related family. It was predicted as high affinity binder based on electronegativity and low hydrophobicity. The computational methods employed were validated using Bet v 1 and Der p 2 allergens where 67% and 60% of the epitope residues were predicted correctly. Among B cell epitopes, Peptide P2 showed maximum IgE binding with individual and pooled patients' sera (mean OD 0.604±0.059 and 0.506±0.0035, respectively) followed by P1, P4 and P3 epitopes. All T cell epitopes showed lower IgE binding.

Conclusion

Four B cell epitopes of C. lunata ADH were identified. Peptide P2 can serve as a potential candidate for diagnosis of allergic diseases.

[Identification of protein antigen for antibody DBD02 by biopanning of T7 phage display library]

AIM

To identify the specificity of mAb DBD02, we developed and optimized a new method by biopanning of T7 Select human liver cDNA phage display library.

METHODS

After two rounds of biopanning, eluted phages were subjected to Dot blot using mAb DBD02 as primary antibody. The positive PFUs (plaque forming unit) which recognized by DBD02 were further confirmed by Western blot, PCR and sequencing.

RESULTS

The antigen recognized by DBD02 was identified as alcohol dehydrogenase. And the epitope for mAb DBD02 was further mapped within a peptide of 22 amino acids (QDYKKPIQEVLKEMTDG-GVDFS).

CONCLUSION

Our data indicate that biopanning of T7 phage display library by mAbs is time, cost, and labor-saving and specific tool for protein antigen identification.

Immunochemical features in the classification of human alcohol dehydrogenase family

Human alcohol dehydrogenase (ADH) constitutes a complex family with diversified functions. Rabbit antihuman class I, II, III, and IV ADH antisera were prepared and used as probes to compare cross-reactivity with the isozymes across classes by semiquantitative Western blotting and quantitative enzyme-linked immunosorbent assay (ELISA). The interclass cross-reactivities with the noncognate isozymes by ELISA, generally approximately 0-35%, appeared considerably lower than those of the intraclass cross-reactivities except with the class IV isozyme. The anti-ADH1B1, ADH1C1, and ADH3 antisera, but not the anti-ADH2, exhibited approximately 80% cross-reactivity with ADH4. The intraclass cross-reactivities among class I isozymes ADH1A, ADH1B1, and ADH1C1 with anti-ADH1B1 or anti-ADH1C1 antisera were approximately 90%. Immunohistochemistry detecting with class-specific antibodies for ADH1-4 isolated from the corresponding antisera demonstrated that ADH4 was the predominant isoform expressed in the basal and suprabasal layer of human esophagus mucosa, whereas it was virtually devoid in the adjacent squamous cell carcinoma. Thus, the setup is more valuable for scanning ADH expression at protein level in different tissues and under different conditions, and maybe not as a tool for classification.

[Administration of the omega-3 polyunsaturated fatty acid drug eiferol decreases alcohol motivation in albino rats by elevating the level of antibodies to alcohol dehydrogenase]

The study experimentally assessed the approach proposed by the authors to lower alcohol motivation, which involves enhancement of a specific immunity at the stage of alcoholization when acetaldehydemodified ethanol exchange enzymes [alcohol dehydrogenase (ADH)] and acetaldehyde dehydrogenase may be expected to occur. Omega-3 polyunsaturated fatty acid (PUFA) drugs enhance the formation of autoantibodies to modified ADH and decrease the activity of ADH in the stomach and liver. At the same time, PUFA drugs can, under certain conditions, produce an anti-alcoholic activity and a positive effect on the psychoemotional status of animals after the ethanol deprivation period.

Antibodies to alpha5beta1 and alpha(v)beta3 integrins react with Candida albicans alcohol dehydrogenase

It has been hypothesized that Candida albicans possesses integrin-like receptors on its cell surface. This is because C. albicans binds numerous fluid-phase extracellular matrix (ECM) proteins on its cell surface and adheres to the same ECM proteins when immobilized. In addition, numerous antibodies to human integrins (receptors for ECM proteins) bind to the fungal cell surface and in so doing inhibit the binding of the respective proteins. To demonstrate the presence of such a cell surface integrin, a cDNA library of C. albicans yeast cells was screened with polyclonal antiserum to the human fibronectin receptor (alpha5beta1 integrin). Clones isolated by this screening technique also reacted specifically to antiserum against the human vitronectin receptor (alpha(v)beta3 integrin). DNA sequence analysis of the cloned insert predicted a 350 aa protein (37 kDa). This predicted protein showed 75% homology at the nucleotide sequence level to alcohol dehydrogenase (ADH) of Saccharomyces cerevisiae. In vitro transcription/translation of the cloned inserts yielded a 37 kDa protein that was immunoprecipitated with antibodies to the alpha5beta1 and alpha(v)beta3 integrins and an antibody to a C. albicans fibronectin receptor. These antibodies and an mAb to the human vitronectin receptor demonstrated an antigen of -37 kDa present in the cell-wall preparations of C. albicans and in spent growth medium. All four antibodies reacted with authentic ADH. The possible significance of these results in relation to C. albicans adherence is discussed.

[Mechanisms of suppression of alcohol motivation after immunization of albino rats against alcohol dehydrogenase I: The role of ADH epitopes and ADH activity in the adrenal glands]

Experimental results have demonstrated a significant decrease in the level of alcohol consumption by albino rats immunized with heterologous horse alcohol dehydrogenase. The role of ADH epitopes 9-14, 93-115, and 265-276 in this phenomenon was examined, and it was established that the latter sequence (265-276) plays the biggest role. The inhibition of ADH activity in the adrenals of immunized rats was much higher compared to the liver. We propose a hypothesis that the effect of alcohol dehydrogenase on alcohol consumption is connected with its role in catecholamine metabolism.

Identification of two liver proteins recognized by autoantibodies elicited in mice infected with mouse hepatitis virus A59

Western blot experiments showed that sera from mice infected with the mouse hepatitis virus strain A59 (MHV-A59) contained autoantibodies (autoAb) that bound to a 40-kDa protein present in liver and kidney extracts. No reaction was observed with extracts of the heart, muscles, spleen, brain and lung. The Ab cross-reacted with a 40-kDa protein from human, rat and sheep liver, but not with liver extracts from the silver side fish (Odontesthes bonariensis). No correlation was found between the development of the hypergammaglobulinemia that followed the viral infection and the occurrence of the autoAb. Reactive immunoglobulins pertained to the IgG1, IgG2a and IgG2b subclasses, recognized cryptic epitopes and were detected from 10 days up to 8 weeks after MHV-infection. The 40-kDa protein was purified from mouse liver extracts by ion-exchange chromatography, gel filtration and SDS-PAGE. Because the N-terminal was blocked, we digested the protein in-gel with trypsin and sequenced various peptides. Results indicated a 100% homology of sequence between the protein recognized by the autoAb and liver fumarylacetoacetate hydrolase (FAH), the enzyme that mediates the last step of tyrosine catabolism. Additionally, a second protein recognized by the autoAb was detected during FAH purification steps and was identified as liver alcohol dehydrogenase.

Structure-function relationships in Drosophila melanogaster alcohol dehydrogenase allozymes ADH(S), ADH(F) and ADH(UF), and distantly related forms

Drosophila melanogaster alcohol dehydrogenase (ADH), a paradigm for gene-enzyme molecular evolution and natural selection studies, presents three main alleloforms (ADHS, ADHF and ADHUF) differing by one or two substitutions that render different biochemical properties to the allelozymes. A three-dimensional molecular model of the three allozymes was built by homology modeling using as a template the available crystal structure of the orthologous D. lebanonensis ADH, which shares a sequence identity of 82.2%. Comparison between D. lebanonensis and D. melanogaster structures showed that there is almost no amino-acid change near the substrate or coenzyme binding sites and that the hydrophobic active site cavity is strictly conserved. Nevertheless, substitutions are not distributed at random in nonconstricted positions, or located in external loops, but they appear clustered mainly in secondary structure elements. From comparisons between D. melanogaster allozymes and with D. simulans, a very closely related species, a model based on changes in the electrostatic potential distribution is presented to explain their differential behavior. The depth of knowledge on Drosophila ADH genetics and kinetics, together with the recently obtained structural information, could provide a better understanding of the mechanisms underlying molecular evolution and population genetics.

Structural and functional divergence of class II alcohol dehydrogenase--cloning and characterisation of rabbit liver isoforms of the enzyme

cDNAs coding for class II alcohol dehydrogenase were isolated from a rabbit-liver cDNA library. Deduced amino acid sequences show that isozymic forms of rabbit class II alcohol dehydrogenase exist, with a positional identity of 88.4%. A high variability in structure of class II alcohol dehydrogenase between the species is also reflected in function. The rabbit II-1 isozyme shows common characteristics with the human enzyme, but has a lower Km value for ethanol, 4.2 mM. The II-2 isozyme shows restriction for aliphatic alcohols longer than pentanol. For shorter alcohols the II-2 form has similar Km values as the II-1 isozyme, 5.5 mM for ethanol, but is a low activity variant with a 10-fold decrease in k(cat) values compared with II-1. Nevertheless, II-2 has a higher specificity for benzoquinone than II-1 due to a lower Km value, 80 microM compared with 1 mM, and is in this sense more like the human class II enzyme. In addition a rabbit class III alcohol dehydrogenase cDNA was isolated that encodes a typical class III enzyme/glutathione-dependent formaldehyde dehydrogenase. The finding of isozymic forms of class II alcohol dehydrogenase is in line with the evolution of the system of medium-chain alcohol dehydrogenases with different enzymes, different classes and different isozymes and further underline the complexity of the entire mammalian alcohol dehydrogenase system.

Alcohol dehydrogenase: a target of humoral autoimmune response in liver disease

BACKGROUND & AIMS

Liver-specific membrane lipoprotein (LSP) is a heterogeneous liver preparation that has been widely used to study autoreactivity in liver disease. The aim of this study was to identify autoantigens in LSP.

METHODS

Guinea pig anti-LSP serum was used to screen a human liver complementary DNA (cDNA) library. Humoral immune responses to isolated potential autoantigens were investigated by immunoblotting in 91 pediatric patients with various liver diseases, 20 adult patients with alcoholic liver disease and 20 with autoimmune thyroid disease, 37 healthy children, and 20 healthy adults.

RESULTS

A 1.6-kilobase cDNA insert isolated from the cDNA library was found to encode amino acids 61-374 of the human alcohol dehydrogenase (ADH)-gamma 1 subunit. Antibodies to this or other ADH subunits were found significantly more frequently in autoimmune liver diseases (19 of 39 patients; 49%), Wilson's disease (5 of 13 patients; 38%), and alcoholic liver disease (10 of 20 patients; 50%) than in normal controls (P < 0.0001, P < 0.005, and P < 0.05, respectively) and correlated with disease activity in autoimmune liver disease.

CONCLUSIONS

ADH has been identified as a new antigenic component of the LSP using a xenogeneic antiserum to immunoprobe a human cDNA liver library and seems to be a target autoantigen in liver disease. This approach may be useful in identifying other potential autoantigens.

Structure and regulation of the Candida albicans ADH1 gene encoding an immunogenic alcohol dehydrogenase

The Candida albicans ADH1 gene encodes an alcohol dehydrogenase which is immunogenic during infections in humans. The ADH1 gene was isolated and sequenced, and the 5'- and 3'-ends of its mRNA were mapped. The gene encodes a 350 amino acid polypeptide with strong homology (70.5-85.2% identity) to alcohol dehydrogenases from Saccharomyces cerevisiae, Kluyveromyces lactis and Schizosaccharomyces pombe. The cloned C. albicans ADH1 gene was shown to be functional through complementation of adh mutations and efficient production of active alcohol dehydrogenase in S. cerevisiae. Northern analysis of C. albicans RNA revealed that ADH1 mRNA levels were regulated in response to carbon source and during batch growth. During growth on glucose, ADH1 mRNA levels rose to maximum levels during late exponential growth phase and declined to low levels in stationary phase. The ADH1 mRNA was relatively abundant during growth on galactose, glycerol, pyruvate, lactate or succinate, and less abundant during growth on glucose or ethanol. Alcohol dehydrogenase levels did not correlate closely with ADH1 mRNA levels under the growth conditions studied, suggesting either that this locus is controlled at both transcriptional and post-transcriptional levels, or that other differentially regulated ADH loci exist in C. albicans.

Surface localization, regulation, and biologic properties of the 96-kDa alcohol/aldehyde dehydrogenase (EhADH2) of pathogenic Entamoeba histolytica

The 96-kDa surface antigen of Entamoeba histolytica was demonstrated through extensive immunologic evaluation with monoclonal and monospecific antibodies to be identical to or an isoform of the amebic alcohol/aldehyde dehydrogenase (EhADH2). EhADH2 was secreted, excreted, or shed into the culture medium in quantities commensurate with amebic growth when studied in a novel culture system. Of importance, using RNase protection assays, specific mRNA coding for the EhADH2 gene product(s) was up-regulated by treatment of viable trophozoites with the enzyme substrate ethanol. These data provide insight into the biology of this enzyme and its regulation by appropriate stressors.

[Detection of antigenic determinants of alcohol dehydrogenase for certain biological species using antipeptide antibodies]

The structural and functional peculiarites of alcohol dehydrogenases (ADH) of some biological species have been studied using antipeptide antibodies (AB). The synthetic peptides were used which corresponded to the functionally important sites (1-14, 93-115, 265-276) of equine liver ADH. Conjugates of peptides with protein carriers were obtained and used for immunization of laboratory animals. It was shown that the antipeptide antibodies formed therefrom could interact with the corresponding synthetic peptides, with conjugates derived from them as well as with the native enzyme. The results of cross-reactivity of antipeptide AB with ADH from other biological sources suggest that amino acid sequences (1-14), (93-115) and (265-276) contain common antigenic determinants for the corresponding ADH from animal sources. According to computer prediction data for linear epitopes of equine liver ADH, sequence (93-115) comprises amino acid residues of the antigenic determinants with enhanced conformational rigidity which is consistent with the literary data on the functional significance of this site (the loop ligating the second Zn atom). Sequences (1-14) and (265-276) contain amino acid residues capable of interacting with AB and pertaining, in all probability, to antigenic determinants formed by mobile structures.

Characterisation of an epitope recognised by a monoclonal antibody against horse alcohol dehydrogenase using peptides synthesised on solid support

Immunological analysis, using the Pepscan technique, of the tetradecapeptide, Pro344-Glu357 (PLITHVLPFEKINE), from horse liver alcohol dehydrogenase has identified a five amino acid sequence, HVLPF, which binds a monoclonal antibody. The epitope seems to be rather flexible with only two of the amino acids, Pro and Phe, having the characteristics of contact residues. However, the presence of the adjacent glutamic acid residue as part of the Pepscan peptide has a dramatic negative neighbourhood effect and inhibits binding. This highlights the potential risk of missing an epitope altogether when using the Pepscan procedure for epitope mapping.

A novel ancestral protein of Drosophila alcohol dehydrogenase in Streptomyces?

Polyclonal antibodies raised against purified Drosophila alcohol dehydrogenase (ADH) were used in Western blot analyses to search for structurally and/or immunologically related proteins in prokaryotes and eukaryotes. No immunological-reactive protein was detected in a flesh fly, a locust, and butterflies. Immunological similarity with the 50-kDa PQQ-glucose dehydrogenase (GluDH)-B enzyme of Acinetobacter calcoaceticus was found, but the cross-reactivity apparently is dependent on the high hydrophilic character of this protein. Antibodies against PQQ-GluDH did not recognize Drosophila ADH. In five of seven species of the gram-positive soil bacteria actinomycetes tested, a protein approximately 28-30 kDa in subunit size was strongly recognized by alpha-DADH. It is probably not one of the two proteins with known homology to Drosophila ADH, viz., the actIII gene product and 20 beta-hydroxysteroid dehydrogenase. The protein is present in both the soluble and the pellet-membrane fraction of the cells. The protein has a late temporal expression in surface-grown cultures and, therefore, might be involved in secondary metabolism.

Influence of the immunization against heterologous alcohol dehydrogenase on liver alcohol dehydrogenase isozymes and alcohol abuse of rats

The possible biochemical and immunological mechanisms of the previously discovered phenomenon of significant and prolonged decrease of alcohol abuse of albino rats after the intravenous injection of the heterologous alcohol dehydrogenase (ADH) were studied. It was found that immunization of rats against horse liver S-ADH result in the appearance of a high titre of antibodies against rat liver ADH-3 isozyme. This isozyme is responsible for the metabolism of 90% of alcohol administrated in vivo. It is shown that immunization against horse liver S-ADH leads also to a significant (2--3-fold) lowering of the activity level of ADH-3 in rat liver. The activity level of the other rat ADH isozymes, ADH-1 and ADH-2, was not found to be changed. The intravenous injection of the specific anti-(horse liver S-ADH) serum, purified by affinity chromatography on immobilized horse liver S-ADH, resulted in a significant decrease of alcohol abuse in alcohol-dependent animals. These results allow us to assume an important role of rat liver ADH-3 in the mechanism of alcohol addiction.

Isolation of a tomato alcohol dehydrogenase 2-encoding cDNA using phage-promoted antibody screening of a plasmid cDNA library

We describe the cloning of a cDNA encoding tomato alcohol dehydrogenase 2 (Adh2) by screening plasmid cDNA clones in phage plaques. A cDNA library constructed in a plasmid vector containing a unique SstI site at the 5' end of the cDNA insert was transferred into the SstI site of the lacZ gene of phage lambda Charon16, and screened by anti-Adh2 antibody to identify reactive plaques. Plasmid cDNA clones were recovered by SstI digestion, ligation, and transformation from phage minipreps for subsequent characterization. This system preserves the original plasmid library for subsequent screening with nucleic acid probes to identify full-length, multiple independent, or related cDNA clones not subject to the selection pressure of phage growth or lysogeny, or negative antibody reactivity. Thirty-two cDNA clones were identified with polyclonal antiserum to Adh2. Three of these reacted with monoclonal anti-Adh2 and only those three hybridized to maize adh1 sequence. One of these cDNAs, Adh31, was further characterized as encoding Adh2 by hybrid-selected translation and high sequence homology with the maize adh1 gene.

Alcohol dehydrogenase (ADH). Influence of homo- and heterologous ADH administration on albino rats craving for alcohol and on ADH isozyme activity in the liver

The effects of homo- and heterologous alcohol dehydrogenase (ADH) administration into albino rats were investigated. It was found that homologous ADH increases and heterologous ADH decreases the craving for ethanol. The latter effect was accompanied by the appearance of anti-ADH-3 antibodies and by a decrease in ADH-3 activity in the liver. Craving for alcohol decreased after both active and passive immunization against ADH.

Developmental profile and tissue distribution of Drosophila alcohol dehydrogenase: an immunochemical analysis with monoclonal antibodies

To analyze Drosophila alcohol dehydrogenase gene (Adh) expression and tissue distribution at various developmental stages, we devised several immunochemical techniques making use of monoclonal antibodies against Drosophila alcohol dehydrogenase (ADH), which had been obtained previously. We here report their application to analyze the expression of Adh in a wild-type strain of D. melanogaster. s-ELISA tests were performed to evaluate fluctuations in ADH content and specific activity during development in individual organs as well as in whole individuals. In all cases, ADH specific activity appeared to be quite constant, which implies that variations in enzyme activity reflect differences in protein content. Immunoblottings of crude homogenates revealed immunoreactive low relative molecular mass peptides in addition to the 27 KD monomeric band, showing a conserved banding pattern in different organs and developmental stages. Immunohistochemical assays on whole organs were used to analyze the general pattern of ADH distribution. Immunoperoxidase staining of cryosections proved to be of crucial relevance, as it yielded full details of the tissue localization of ADH within the ADH-positive organs. We have shown not only that ADH displays a specific distribution in some organs but also that the enzyme is restricted to certain cell types.

The 40-kilodalton allergen of Candida albicans is an alcohol dehydrogenase: molecular cloning and immunological analysis using monoclonal antibodies

To characterize the 40-kilodalton (kD) major allergen of Candida albicans (C. albicans), six monoclonal antibodies (MoAbs) against this allergen were generated. In SDS-polyacrylamide gel electrophoresis and immunoblot analysis, these MoAbs showed four different reaction patterns to antigens of six different Candida species. With the exception of one MoAb, other MoAbs were resistant to periodate treatment indicating non-carbohydrate epitopes were probably being recognized by these MoAbs. These MoAbs were used in the molecular cloning and immunological analysis of the gene coding for the 40-kD allergen. Nucleotide sequence determination of the two lambda gt11 cDNA clones obtained showed that the 40-kD allergen is an alcohol dehydrogenase (ADH) which shares a 70% amino acid sequence homology with the ADH isozyme I of Saccharomyces cerevisiae. This finding was confirmed by positive immunological response of the lysates of the clones obtained and a preparation of ADH of Saccharomyces cerevisiae to various MoAbs and to IgE antibodies in sera of allergic patients.

Use of in vitro mutagenesis to analyze the molecular basis of the difference in Adh expression associated with the allozyme polymorphism in Drosophila melanogaster

In natural populations of Drosophila melanogaster, the alcohol dehydrogenase (Adh) locus is polymorphic for two allozymes, designated Slow and Fast. Fast homozygotes generally have a two- to threefold higher ADH activity level than Slow homozygotes for two reasons: they have a higher concentration of ADH protein and the Fast protein has a higher catalytic efficiency. DNA sequencing studies have shown that the two allozymes generally differ by only a single amino acid at residue 192, which must therefore be the cause of the catalytic efficiency difference. A previous P element-transformation experiment mapped the difference in ADH protein level to a 2.3-kb HpaI/ClaI restriction fragment; which contains all of the Adh coding sequences but excludes all of the 5' flanking region of the distal transcriptional unit. Here we report the results of a site-directed in vitro mutagenesis experiment designed to investigate the effects of the amino acid replacement. This replacement has the expected effect on catalytic efficiency, but there is no detectable effect on the concentration of ADH protein estimated immunologically. This result shows that the average difference in ADH protein level between the allozymic classes is due to linkage disequilibrium between the amino acid replacement and one or more other polymorphisms within the HpaI/ClaI fragment. Sequence analysis of several Fast and Slow alleles suggested that the other polymorphism might be a silent substitution at nucleotide 1443, but another in vitro mutagenesis experiment reported here shows that this is not the case. Therefore, the molecular basis of the difference in ADH protein concentration between the allozymic classes remains an open question.

Associations between DNA sequence variation and variation in expression of the Adh gene in natural populations of Drosophila melanogaster

A large part of the genetic variation in alcohol dehydrogenase (ADH) activity level in natural populations of Drosophila melanogaster is associated with segregation of an amino acid replacement polymorphism at nucleotide 1490, which generates a difference in electrophoretic mobility. Part of the allozymic difference in activity level is due to a catalytic efficiency difference, which is also caused by the amino acid replacement, and part is due to a difference in the concentration of ADH protein. A previous site-directed in vitro mutagenesis experiment clearly demonstrated that the amino acid replacement has no effect on the concentration of ADH protein, nor does a strongly associated silent polymorphism at nucleotide 1443. Here we analyze associations between polymorphisms within the Adh gene and variation in ADH protein level for a number of chromosomes derived from natural populations. A sequence length polymorphism within the first intron of the distal (adult) transcript, 1, is in strong linkage disequilibrium with the amino acid replacement. Among a sample of 46 isochromosomal lines analyzed, all but one of the 14 Fast lines have 1 and all but one of the 32 Slow lines lack 1. The exceptional Fast line has an unusually low level of ADH protein (typical of Slow lines) and the exceptional Slow line has an unusually high level (typical of Fast lines). These results suggest that the 1 polymorphism may be responsible for the average difference in ADH protein between the allozymic classes. A previous experiment localized the effect on ADH protein to a 2.3-kb restriction fragment. DNA sequences of this fragment from several alleles of each allozymic type indicate that no other polymorphisms within this region are as closely associated with the ADH protein level difference as the 1 polymorphism.

Activation and inhibition of human alcohol dehydrogenase by monoclonal antibodies

The human class I alcohol dehydrogenase isozyme beta 2 beta 2 was used as the antigen to raise monoclonal antibodies. Altogether seven lines of hybridomas secreting monoclonal antibodies were obtained. None of the antibodies was isozyme specific and all of them exhibited a similar affinity against all isozymes of the human class I ADH. Five out of the seven monoclonal antibodies had no effect on beta 2 beta 2 activity. Antibody G3 acted as a non-competitive inhibitor with a KI of 3 micrograms/ml at pH 7.5. Increasing pH was effective in reducing the level of inhibition. On the other hand, antibody 1D4 exhibited a pH-dependent activation of ADH activity. In the presence of this antibody, the pH optimum of beta 2 beta 2 was shifted from 9 to 8.5 and total activity was increased by 70% at this optimal pH. Kinetic analysis indicates that 1D4 probably acts as a non-competitive activator and may exert its action by interacting with the coenzyme binding site.

Localization of pulmonary carbonyl reductase in guinea pig and mouse: enzyme histochemical and immunohistochemical studies

We studied the localization of carbonyl reductase (E.C. 1.1.1.184) in guinea pig and mouse lung by enzyme histochemistry and immunohistochemistry, using antibodies against the guinea pig lung enzyme which crossreacted with the lung enzymes of both animals. Carbonyl reductase activity was detectable in the bronchiolar epithelial cells of small airways and in alveolar cells. In the immunohistochemical staining for carbonyl reductase, the reaction was strongest in the non-ciliated bronchiolar cells (Clara cells) and was weak in the ciliated cells and type II alveolar pneumocytes. Injection of a single dose of naphthalene led to significant impairment of carbonyl reductase activity and of microsomal mixed-function oxidase activities in mouse lung, with a marked decrease in both activity and immunoreactive staining in the bronchiolar epithelial cells. The results indicate that carbonyl reductase is localized primarily in the Clara cells, which are known to be sites of pulmonary drug metabolism.

Immunological and enzymological localization of carbonyl reductase in ovary and liver of various species

The tissue distribution of carbonyl reductase in ovary and liver of various animal species was investigated by measuring the reduction of 13,14-dihydro-15-keto-prostaglandin F2a, a specific substrate for rat ovarian carbonyl reductases, and by means of Western blotting analysis using anti-rat ovarian carbonyl reductase antibody. The highest ovarian carbonyl reductase activity towards 13,14-dihydro-15-keto-PGF2a was found in rat among ten animal species tested, followed by hamster and monkey. The immunoreactive protein was detected in hamster and monkey ovaries. Although carbonyl reductase activity towards 13,14-dihydro-15-keto-PGF2a was not detectable in non-pregnant rabbit ovary, pregnant rabbit ovary showed not only moderate activity but also immunoreactivity with anti-rat ovarian carbonyl reductase antibody. On the other hand, carbonyl reductase activity towards 13,14-dihydro-15-keto-PGF2a was detected in hepatic tissue of all the species tested, except for rat and left-eye flounder. Immunoreactive proteins were present in hepatic tissue of various species that exhibited measurable carbonyl reductase activity towards 13,14-dihydro-15-keto-PGF2a.

Gene regulation during anaerobiosis in soya roots

The proteins of soybean roots undergoing anaerobiosis can be grouped into three classes. Class 1 proteins are induced severalfold and at least 28 of these were identified by in vivo labeling. These proteins include the enzymes alcohol dehydrogenase (ADH), fructose aldolase, pyruvate decarboxylase, phosphoglucomutase, and lactate dehydrogenase. Class 2 proteins include such enzymes as glucose phosphate isomerase, sucrase, and malate dehydrogenase; their specific activity remains constant in aerobiosis or anaerobiosis. The third class of proteins includes those enzymes such as peroxidase whose activity decreases more than 90% after just 1 day in anaerobiosis. Immunoblotting coupled with two-dimensional chromatography of in vitro translated plant extracts demonstrated that ADH level during anaerobiosis is controlled by its mRNA concentration. Little or no mRNA for ADH was detected in aerobically grown roots. This suggests that the increased level of ADH activity is due to de novo synthesis of the mRNA rather than activation of a sequestered mRNA or superactivation of the protein.

Inter-specific analysis of Drosophila alcohol dehydrogenase by an immunoenzymatic assay using monoclonal antibodies

Three Drosophila alcohol dehydrogenase monoclonal antibodies have been prepared and characterized. These antibodies cross-react with alcohol dehydrogenase from different species as revealed by immunoblotting assay. An enzyme-linked immunosorbent assay has been devised to quantify alcohol dehydrogenase in several species, different strains and individual larval organs. The assay detects alcohol dehydrogenase via a double-antibody sandwich assay technique giving strictly proportional values for antigen concentration and optical densities in the range of 3-30 ng of antigen per 100 microliters of sample. When alcohol dehydrogenase specific activity is compared in different larval organs a remarkable similarity is observed, whereas protein distribution varies substantially. Larval fat body and larval alimentary canal contribute 63% and 26% respectively to recovered alcohol dehydrogenase.

A new alcohol dehydrogenase, reactive towards methanol, from Bacillus stearothermophilus

An NAD+-dependent alcohol dehydrogenase (ADH) was purified to homogeneity from an aerobic strain of Bacillus stearothermophilus, DSM 2334 (ADH 2334), and compared with the ADH from B. stearothermophilus NCA 1503 (ADH 1503). When an antibody raised against ADH 2334 was used, no cross-reactivity with ADH 1503 was observed on Western blots; by means of an enzyme-linked-immunoabsorbent-assay ('e.l.i.s.a.') procedure, it was found that ADH 1503 had less than 6% of the antigenic activity of ADH 2334. Amino acid analyses detected very small differences in composition, equivalent to about 40 sequence changes, between the two enzymes. The new enzyme has the same six-amino-acid N-terminal sequence as ADH 1503. ADH 2334, but not ADH 1503, is reactive towards methanol; both enzymes can oxidize ethanol, propan-1-ol, butan-1-ol and butan-2-ol. The new enzyme has a distinctive pH optimum at pH 5.5-6 and has significantly lower KEthanolm and kEthanolcat. values than those of ADH 1503. From steady-state kinetic parameters of the reaction with ethanol, propan-1-ol and butan-1-ol, it was shown that ADH 2334 has an ordered mechanism in both directions, with NAD+ being the compulsory first substrate in alcohol oxidation and NADH release being the rate-limiting step. ADH 1503 has an ordered addition of NAD+ and alcohol, but NADH release is not rate-limiting.

A new means of inducibly inactivating a cellular protein

This paper presents a general means of eliminating the function of a single protein without relying on genetic alterations in its structure or level of synthesis. The strategy is based on the inducible cellular expression of neutralizing antibody to inactivate the protein selectively. The feasibility of this approach is illustrated by using alcohol dehydrogenase I (ADH I) in Saccharomyces cerevisiae as a model. Heavy- and light-chain cDNAs were isolated from a hybridoma secreting an antibody which neutralizes yeast ADH I. The cDNAs were characterized with respect to their length and identity, their signal sequences were removed, and synthetic translation initiation codons were joined to them. These truncated sequences were then inserted into an inducible expression vector and shown to be expressed as stable heavy and light chains, which assemble and bind antigen. The sequences were introduced into yeast mutants containing different levels of ADH activity, and evidence is provided that the antibodies produce limited neutralization of enzyme activity in vivo. In principle, the approach can be used for any cell type in which functional antibody can be inducibly expressed.

Molecular tools for inactivating a yeast enzyme in vivo

As part of an effort to develop a new means of inducibly inactivating cellular proteins in vivo, three monoclonal antibodies which neutralize yeast alcohol dehydrogenase (ADH) activity were isolated and characterized with respect to criteria important for the inactivation strategy. The significance of these criteria is considered, and a general means of generating appropriate antibodies is suggested. All three antibodies described here were specific for ADH I; they did not recognize the closely related isozyme ADH II in a plate-binding assay and did not immunoprecipitate molecules other than ADH from a Saccharomyces cerevisiae extract. Neutralization occurred in a yeast extract and, for two antibodies, was blocked by high concentrations of the coenzyme NAD+. This finding suggests that the antibodies may block enzyme activity by stabilizing an inactive form of ADH lacking bound NAD+. These results provide a foundation for the use of these antibodies to inactivate ADH in vivo.

Purification of aldose reductase from human placenta and stabilization of the inhibitor binding site

Aldose reductase from human placenta was purified to homogeneity by a rapid (2 day) and efficient purification scheme involving Red Sepharose affinity chromatography, chromatofocusing and high performance liquid chromatography on a size-exclusion column. Addition of NADP+ at all steps in the purification of aldose reductase and during storage of the enzyme at -20 degrees stabilized both the enzyme active site and the major site for binding of aldose reductase inhibitors such as sorbinil and tolrestat. Aldose reductase is a monomer with a molecular mass of 38 kD by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, apparent pI 5.9. Placenta aldose reductase exhibited no cross-reactivity with aldehyde reductase from human liver in an ELISA assay. Aldose reductase showed broad specificity for aldehydes, was specific for NADPH, and was activated by sulfate.

Activation of low and null activity isozymes of maize alcohol dehydrogenase by antibodies

Antisera were raised against several purified, high specific activity isozymes of maize alcohol dehydrogenase (ADH1). The various antisera had different effects on the activity of immunoprecipitated ADH. One antiserum completely inactivated maize ADH. This inactivation could be blocked by preincubation of the enzyme with NAD+, its cofactor, or with NADP. The different antisera were used to analyze variant forms of ADH1. Isozymes having lowered specific activity were activated to wild-type levels by precipitation of the enzymes with noninactivating antisera. Isozymes having no detectable ADH activity (CRM+ nulls) were activated by immunoprecipitation with noninactivating antisera when preincubated with NAD+ or NADP. All of the CRM+ nulls were shown to be unable to bind NAD+, a flaw which can account for their lack of activity. The results indicate that a conformational equilibrium between active and inactive forms of maize ADH in solution controls the specific activity of the various isozymes. Both NAD+ and antibodies raised against high specific activity enzymes can interact with low activity isozymes to shift the balance of the equilibrium toward the active form, thus increasing their specific activity.

Cross-reactive monoclonal antibodies to alcohol dehydrogenases

Three anti-horse liver alcohol dehydrogenase (HLADH) monoclonal antibodies are described. Two are specific for ADH and cross-react with class I and II enzymes from mouse, horse and Chinese hamster. They are specific for the native enzyme but do not inhibit enzyme activity except when combined at high concentration. The third antibody was isolated as a response to rabbit metallothionein. It binds metalloproteins and inhibits ADH activity.

The partial characterization of alcohol dehydrogenase null alleles from natural populations of Drosophila melanogaster

Twenty-three alcohol dehydrogenase (ADH) putative null alleles extracted from four Tasmanian (Australia) populations of Drosophila melanogaster produce no ADH activity and are unable to form active heterodimers with either AdhF or AdhS. Twelve of these nulls were tested by enzyme-linked immunosorbent assay (ELISA) and did not produce any ADH cross-reacting material (CRM). The null homozygotes had similar, but slightly lower, mortalities on ethanol-supplemented media compared to an artificially induced null allele. Heterozygotes between the null alleles and standard AdhF and AdhS alleles had intermediate ADH activity and CRM levels.

Immunological cross-reactivity of alcohol dehydrogenase (ADH) isozymes with rabbit immune sera against horse and human ADH subunits

Rabbit immune sera raised against denatured forms of horse liver alcohol dehydrogenase and of human ADH5 isozyme were found to react with the denatured subunits of all the human ADH isozymes regardless of their class. The immune serum against the human ADH isozyme cross-reacted also with horse ADH subunits and, at appropriate dilutions, both the immune sera reacted with denatured yeast ADH, suggesting that common structures have been preserved in these molecules over a long evolutionary period. The immune sera partially reacted also with the respective antigens in their native conformation, indicating that some 'sequential' epitopes are expressed on the surface of the folded proteins.