Related Experiment Video
Updated: Aug 2, 2026
07:28
An Inexpensive, Scalable Behavioral Assay for Measuring Ethanol Sedation Sensitivity and Rapid Tolerance in Drosophila
Published on: April 15, 2015
Human aldehyde dehydrogenase isozymes and alcohol sensitivity
Isozymes
|January 1, 1987
Summary
An inherited deficiency in aldehyde dehydrogenase (ALDH) I isozyme causes alcohol sensitivity and the flushing response in East Asian populations. This ALDH I deficiency is linked to a lower incidence of alcoholism in these groups.
Area of Science:
- Biochemistry
- Human Genetics
- Pharmacology
Background:
- Acetaldehyde metabolism is crucial due to its toxic effects.
- Two main human hepatic aldehyde dehydrogenase (ALDH) isozymes, ALDH I and ALDH II, exhibit distinct structural and functional characteristics.
- ALDH I is a low Km mitochondrial enzyme, while ALDH II is a higher Km cytosolic enzyme.
Purpose of the Study:
- To investigate the genetic basis of alcohol sensitivity.
- To understand the role of ALDH I isozyme deficiency in the flushing response.
- To explore the implications of ALDH polymorphism on alcoholism incidence.
Main Methods:
- Biochemical assays
- Immunochemical analysis
- Molecular genetics studies
- Population genetic surveys
- Family pedigree analysis
Main Results:
- An inherited deficiency of the ALDH I isozyme, prevalent in Oriental populations, causes acute alcohol sensitivity (flushing response).
- A structural mutation in the ALDH I gene leads to loss of catalytic activity.
- ALDH I isozyme deficiency is inherited in an autosomal codominant manner.
- ALDH polymorphism correlates with a lower incidence of alcoholism in Japanese, Chinese, and Korean populations.
Conclusions:
- ALDH I isozyme deficiency is a primary cause of alcohol sensitivity and flushing response.
- This genetic trait may act as a deterrent against excessive alcohol consumption.
- ALDH polymorphism significantly influences alcoholism rates in specific ethnic groups.
Related Concept Videos
02:23Alcohols from Carbonyl Compounds: Reduction
Reduction is a simple strategy to convert a carbonyl group to a hydroxyl group. The three major pathways to reduce carbonyls to alcohols are catalytic hydrogenation, hydride reduction, and borane reduction.
Catalytic hydrogenation is similar to the reduction of an alkene or alkyne by adding H2 across the pi bond in the presence of transition metal catalysts like Raney Ni, Pd–C, Pt, or Ru. Aldehydes and ketones can be reduced by this method, often under mild to moderate heat (25–100°C) and...
Catalytic hydrogenation is similar to the reduction of an alkene or alkyne by adding H2 across the pi bond in the presence of transition metal catalysts like Raney Ni, Pd–C, Pt, or Ru. Aldehydes and ketones can be reduced by this method, often under mild to moderate heat (25–100°C) and...
02:37Oxidation of Alcohols
In this lesson, the oxidation of alcohols is discussed in depth. The various reagents used for oxidation of primary and secondary alcohols are detailed, and their mechanism of action is provided.
The process of oxidation in a chemical reaction is observed in any of the three forms:
The process of oxidation in a chemical reaction is observed in any of the three forms:
01:29IR and UV–Vis Spectroscopy of Aldehydes and Ketones
Infrared spectroscopy, also known as vibrational spectroscopy, is mainly used to determine the types of bonds and functional groups in molecules. In aldehydes and ketones, the carbonyl (C=O) bond shows an absorption around 1710 cm-1. The C=O bond vibration of an aldehyde occurs at lower frequencies than that of a ketone. In addition to the C=O absorption in an aldehyde, the aldehydic C–H bond also gives two peaks in the 2700–2800 cm-1 range. This absorption, coupled with the C=O stretching, is...
01:19Aldehydes and Ketones with Alcohols: Hemiacetal Formation
Similar to water, alcohols can add to the carbonyl carbon of the aldehydes and ketones. The addition of one molecule of alcohol to the carbonyl compound forms the hemiacetal or half acetal. As depicted below, in a hemiacetal, the carbon is directly linked to an OH and OR group.
01:15Oxidations of Aldehydes and Ketones to Carboxylic Acids
Oxidation of aldehydes and ketones results in the formation of carboxylic acids. Aldehydes, bearing hydrogen next to the carbonyl group, are easily oxidized compared to ketones. This is because an aldehydic proton can easily be abstracted during oxidation.
Aldehydes readily undergo oxidation in strong oxidizing agents such as potassium permanganate and chromic acid. The oxidation can also be carried out using mild oxidizing agents such as silver oxide. In fact, aldehydes can be easily oxidized...
Aldehydes readily undergo oxidation in strong oxidizing agents such as potassium permanganate and chromic acid. The oxidation can also be carried out using mild oxidizing agents such as silver oxide. In fact, aldehydes can be easily oxidized...
01:15NMR Spectroscopy and Mass Spectrometry of Aldehydes and Ketones
In aldehydes, the hydrogen atom connected to the carbonyl carbon helps distinguish aldehydes from other carbonyl compounds using ¹H NMR spectroscopy. The closeness of aldehydic hydrogen to the electrophilic carbonyl carbon highly deshields the hydrogen atom causing its signal to appear around 10 ppm in the ¹H NMR spectra. α hydrogens split the aldehydic proton signal, which helps identify the number of α hydrogens in the molecule. For instance, one α hydrogen creates a doublet for an aldehydic...