IS200 ADH1A refers to the immunological standard or internal standard used in ELISA-based quantification of Alcohol Dehydrogenase 1A (ADH1A) — a key enzyme in human ethanol and retinol metabolism. ADH1A belongs to the class I alcohol dehydrogenase family and is predominantly expressed in the liver, with roles extending into retinoid metabolism and fatty acid oxidation.
Accurate quantification of IS200ADH1A is critical in studies spanning alcoholic liver disease, pharmacogenomics, and developmental biology — fields in which precise enzyme-level data shape mechanistic understanding and therapeutic strategy.
What Is Alcohol Dehydrogenase 1A (ADH1A)?
ADH1A is encoded by the ADH1A gene on chromosome 4q23 and catalyzes the NAD⁺-dependent oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones. Along with ADH1B and ADH1C, it constitutes the major alcohol-oxidizing system in the human liver. ADH1A is a dimeric zinc-containing enzyme with Km values that differ from other ADH isoforms, giving it unique kinetic properties at varying ethanol concentrations. Its relatively low Km for ethanol means that ADH1A is the dominant isoform active at low blood alcohol concentrations — the physiologically relevant range during moderate alcohol consumption — while ADH1B and ADH1C become more prominent at higher concentrations.
Physiological and Research Significance
ADH1A plays a central role in several metabolic contexts:
- Ethanol metabolism: First-pass oxidation of ingested ethanol to acetaldehyde
- Retinol (Vitamin A) metabolism: Oxidation of retinol to retinal, linking ADH1A to vitamin A signaling and embryonic development
- Alcoholic liver disease (ALD): Altered ADH1A activity or expression is associated with hepatic injury and inflammation
- Pharmacogenomics: ADH1A polymorphisms influence individual differences in ethanol clearance and alcohol use disorder risk
The connection between ADH1A and retinoic acid biosynthesis is particularly notable: by converting retinol to retinal as an intermediate step toward all-trans retinoic acid (ATRA), ADH1A participates in signaling pathways governing embryonic patterning and cell differentiation. Changes in hepatic ADH1A expression may therefore have pleiotropic effects beyond ethanol metabolism, affecting vitamin A-dependent processes across multiple organ systems.
IS200 and ELISA Kit Formats for ADH1A
In the context of enzyme quantification kits, IS200 typically denotes an internal standard calibrator included within the ELISA kit to correct for plate-to-plate variability and ensure accurate interpolation from the standard curve. ELISA kits designed to quantify ADH1A in human samples typically use a sandwich format with capture and detection antibodies specific for human ADH1A, recombinant ADH1A protein standards for generation of calibration curves in ng/mL or pg/mL, and compatible sample matrices including serum, plasma, liver tissue homogenate, and cell lysates. The inclusion of an IS200-level internal standard is a meaningful quality control feature: it allows researchers to apply a normalization correction when sample-to-sample matrix effects cause slight shifts in assay performance across plate positions or experimental batches.
Assay Protocol Overview
A standard ADH1A ELISA protocol involves sample preparation using cell lysates or tissue homogenates in appropriate lysis buffer, followed by serial dilution of recombinant ADH1A standard to generate the calibration curve. Sample and standards are added to antibody-coated wells for capture incubation, followed by biotinylated anti-ADH1A detection antibody incubation, streptavidin-HRP incubation, TMB substrate development, and absorbance reading at 450 nm. Sample concentrations are back-calculated from the standard curve using four-parameter logistic (4PL) curve fitting, which provides the most accurate interpolation across the full dynamic range of the assay.
Applications in Research and Clinical Studies
- Liver function studies: Quantifying ADH1A in hepatocytes or liver biopsies
- Metabolic research: Assessing enzyme activity correlation with protein levels
- Toxicology: Studying ADH1A response to ethanol exposure in vitro
- Biomarker discovery: Identifying ADH1A as a serum marker for hepatocellular damage
In the context of non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) research, ELISA-based ADH1A quantification in tissue homogenates provides a complement to enzymatic activity assays, helping distinguish whether changes in alcohol metabolism arise from altered ADH1A protein levels, changes in isoform distribution, or post-translational modifications affecting enzyme function. These distinctions are important for selecting pharmacological interventions and interpreting the results of gene expression studies.
Conclusion
IS200 ADH1A ELISA kits provide a sensitive, quantitative platform for measuring alcohol dehydrogenase 1A protein levels in human biological samples. Given ADH1A’s central roles in ethanol and retinol metabolism, accurate quantification supports research spanning liver disease, pharmacogenomics, developmental biology, and toxicology. Selecting a kit with validated IS200 internal standards ensures robust, reproducible data across experimental batches, providing the analytical confidence needed for both mechanistic studies and biomarker validation programs.
