Roger S. Holmes

Recommended nomenclature for five mammalian carboxylesterase gene families: human, mouse, and rat genes and proteins

Mammalian carboxylesterase (CES or Ces) genes encode enzymes that participate in xenobiotic, drug, and lipid metabolism in the body and are members of at least five gene families. Tandem duplications have added more genes for some families, particularly for mouse and rat genomes, which has caused confusion in naming rodent Ces genes. This article describes a new nomenclature system for human, mouse, and rat carboxylesterase genes that identifies homolog gene families and allocates a unique name for each gene. The guidelines of human, mouse, and rat gene nomenclature committees were followed and “CES” (human) and “Ces” (mouse and rat) root symbols were used followed by the family number (e.g., human CES1). Where multiple genes were identified for a family or where a clash occurred with an existing gene name, a letter was added (e.g., human CES4A; mouse and rat Ces1a) that reflected gene relatedness among rodent species (e.g., mouse and rat Ces1a). Pseudogenes were named by adding “P” and a number to the human gene name (e.g., human CES1P1) or by using a new letter followed by ps for mouse and rat Ces pseudogenes (e.g., Ces2d-ps). Gene transcript isoforms were named by adding the GenBank accession ID to the gene symbol (e.g., human CES1_AB119995 or mouse Ces1e_BC019208). This nomenclature improves our understanding of human, mouse, and rat CES/Ces gene families and facilitates research into the structure, function, and evolution of these gene families. It also serves as a model for naming CES genes from other mammalian species.

Ultraviolet light-induced pathology in the eye: associated changes in ocular aldehyde dehydrogenase and alcohol dehydrogenase activities.

Adult male C57BL/6J inbred mice were subjected to ultraviolet radiation (UVR) exposure (302-nm peak wavelength; average intensity 282 (µ W/cm2) for 1 h and monitored for ocular aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) activity changes over a period of 25 days. Dramatic reductions in activities were observed by 4-6 days postexposure, resulting in enzyme levels of 15-16% of control animals. Major decreases in corneal enzyme levels were predominantly responsible for these changes. Ocular morphology was observed throughout using a photoslit-lamp biomicroscope, with maximum corneal clouding occurring at days 4-6. These data support earlier proposals for major roles for these corneal enzymes in assisting the cornea in protecting the eye against UVR-induced tissue damage.

Genetics and ontogeny of alcohol dehydrogenase isozymes in the mouse: Evidence for a cis-acting regulator gene (Adt-1) controlling C2 isozyme expression in reproductive tissues and close linkage of Adh-3 and Adt-1 on chromsome 3

An electrophoretic variant previously reported for the stomach isozyme of alcohol dehydrogenase (ADH-C2) in inbred strains of Mus musculus (Holmes, 1977) has been used to localize the gene encoding this enzyme (Adh-3) on chromosome 3 near Va (varitint) (9.6 ± 3.6% recombinants). Genetic variation of ADH-C2 activity in male and female reproductive tissues among inbred strains and Harwell linkage testing stocks was also observed. Reproductive tissue ADH-C2 phenotypes were inherited in a normal Mendelian fashion among F2 progeny of an F1 (LII × C57BL/Go) × C57BL/Go backcross as though controlled by a single cis-acting regulator locus (designated Adt-1) with two alleles: Adt-1a (presence of ADH-C2) and Adt-1b (absence or low activity of ADH-C2). No recombinants were observed among 73 progeny or among 13 inbred strains and six Harwell linkage testing stocks of mice, indicating that Adh-3 and Adt-1 are closely linked or identical genes. A single recombinant phenotype was observed in Peru-Coppock mice, suggesting that they are separate genes. Ontogenetic analyses demonstrated that ADH-B2 is present throughout development from late fetal stages in stomach, liver, and kidney; similar results were found for ADH-C2 in developing kidney and stomach extracts, whereas ADH-A2 exhibited high activity in liver extracts after 3 weeks of age in both sexes and in male kidney extracts after 6 weeks.

Human ocular aldehyde dehydrogenase isozymes: Distribution and properties as major soluble proteins in cornea and lens

Human aldehyde dehydrogenase isozymes (ALDHs; EC 1.2.1.3) exhibit very high levels of activity in anterior eye tissues. Human corneal ALDH1 and ALDH3 isozymes are present as major soluble proteins (3% and 5%, respectively, of corneal soluble protein) and may play major roles in protecting the cornea against ultraviolet radiation (UVR)-induced tissue damage, as well as contributing directly to ultraviolet B (UV-B) photoreception. The human lens exhibits high levels of ALDH1 activity (1-2% of lens-soluble protein) and lower levels of ALDH3 activity. Kinetic analyses support a role for these enzymes in the metabolism of peroxidic aldehydes, which have been reported in ocular tissues.

Genetics, ontogeny, and testosterone inducibility of aldehyde oxidase isozymes in the mouse: Evidence for two genetic loci (Aox-1 and Aox-2) closely linked on chromosome 1

Abstract“Null”-activity and low-activity variants for the liver supernatant isozymes of aldehyde oxidase (designated AOX-1 and AOX-2) were observed in inbred strains and in Harwell linkage testing stocks of Mus musculus. The genetic loci determining the activity of these isozymes (designated Aox-1 and Aox-2, respectively) are closely linked on chromosome 1 near Id-1 (encoding the soluble isozyme of isocitrate dehydrogenase). Linkage data of Aox-1 with Id-1 and Dip-1 (encoding a kidney peptidase) demonstrated that this gene coincides with or is closely linked to Aox (Watson et al., 1972). Ontogenetic analyses demonstrated that liver AOX-1 appeared just before birth and increased in activity during postnatal development, whereas liver AOX-2 was observed only during postnatal development. Adult male livers exhibited higher AOX-1 and AOX-2 activities than adult female livers. Both isozymes were significantly reduced in activity by castration of adult males and increased following testosterone administration to castrated males and normal female mice.

l‐α‐Hydroxyacid Oxidase Isozymes

L-alpha-Hydroxyacid oxidase isozymes from rat liver (A isozyme) and kidney (B isozyme) have been isolated in a high state of purity with specific activities of 61 and 14.7 microkatals per gram protein respectively. The subunit molecular weights determined by sodium dodecylsulphate polyacrylamide gel electrophoresis were 40000 +/- 3000; the mouse A and B isozymes were also partially purified and their subunit molecular weights shown to be 37000.

Genetics and ontogeny of aldehyde dehydrogenase isozymes in the mouse. Localization of ahd-1 encoding the mitochondrial isozyme on chromosome 4.

Electrophoretic variants for the mitochondrial isozyme of aldehyde dehydrogenase (AHD) have been observed in inbred strains and in Harwell linkage testing stocks of Mus musculus. F1 (LVC×C57BL/Go) mice showed a codominant allele three-banded phenotype, which suggests a dimeric subunit structure (designated AHD-A2). The anodal-migrating supernatant isozyme of AHD was electrophoretically invariant among the 23 inbred strains and stocks examined. The genetic locus encoding AHD-A2 (suggested name Ahd-1) is localized on chromosome 4 and was mapped close to je (jerker) and Gpd-1 (encoding the liver and kidney isozyme of glucose-6-phosphate dehydrogenase). Ontogenetic analyses demonstrated that both AHD isozymes exhibited low activity in late fetal and early neonatal liver and kidney extracts, and reached adult levels within 3 weeks of birth.

Purification and molecular properties of alcohol dehydrogenase from Drosophila melanogaster: Evidence from NMR and kinetic studies for function as an aldehyde dehydrogenase

Abstract 1. 1. Alcohol dehydrogenase (ADH) allozymes (FF, SF, SS) were purified to homogeneity from strains of Drosophila melanogaster using a new procedure. 2. 2. All allozymes displayed aldehyde dehydrogenase activity on cellulose (ALDH) acetate zymograms, corresponding to the ADH activity zones. 3. 3. Kinetic analyses with acetaldehyde as substrate revealed non-linear, biphasic Lineweaver-Burk plots giving two apparent Michaelis constants ( K m ) ranges for the allozymes of 1–10 μM and 0.1–1 mM. 4. 4. In contrast, kinetic analyses with ethanol as substrate gave results consistent with a single K m value of approximately 2 mM. 5. 5. At approx. 3 μM substrate concentration, the enzymes exhibited equivalent rates of dehydrogenase activity with either ethanol or acetaldehyde; whereas at a concentration of 10 mM, the ADHs exhibited approx. a 10-fold higher activity with ethanol as substrate. 6. 6. The specific activity of ADH-FF was 2–3 times higher than ADH-SS with both ethanol and acetaldehyde as dehydrogenase substrates. ADH and ALDH activities were inhibited by pyrazole, disulphiram and p -hydroxymercuribenzoate. 7. 7. Atomic absorption spectrometry confirmed the absence of zinc. 8. 8. The oxidation of 2-[ 13 C]-labelled ethanol by ADH allozymes in vitro was studied using nuclear magnetic resonance spectrometry. 9. 9. Acetaldehyde, its diol and acetate were detected within 20 min and monitored for 10 hr. 10. 10. The significance of these results for studies on ethanol metabolism in D. melanogaster is discussed.

Differential corneal sensitivity to ultraviolet light among inbred strains of mice. Correlation of ultraviolet B sensitivity with aldehyde dehydrogenase deficiency.

Adult male mice from four inbred albino strains (SJL/J, NZW/BL, BALB/c HeA, and SWR/J) were subjected to ultraviolet radiation (UVR) exposure (302 nm peak wavelength, intensity 398 µW/cm2 for 3.25 min and photographed 4 days postexposure to assess corneal clouding. Corneal extracts from control (unexposed) mice from each strain, were also monitored for aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) activity and soluble protein content. The SWR/J strain exhibited more extensive corneal clouding after UV exposure than did the other strains, and control SWR/J mice exhibited a low activity variant phenotype for the major ocular ALDH AHD-4, and decreased levels of soluble protein in corneal extracts. These data support earlier proposals for a major role for ALDH in assisting the cornea in protecting the eye against UVR-induced tissue damage.

Genetics and Ontogeny of Aldehyde Dehydrogenase Isozymes in the Mouse: Evidence for a Locus Controlling the Inducibility of the Liver Microsomal Isozyme.

Variation in the inducibility of the liver microsomal isozyme of aldehyde dehydrogenase (designated AHD-Cy) by phenobarbital administration was observed among inbred strains and linkage testing stocks of Mus musculus. The phenotypes were inherited in a normal Mendelian fashion with two alleles showing codominance at a proposed regulatory locus (designated Ahd-3r). Strain variation was also observed for the induction of liver AHD-Cy by 17-β-oestradiol administration to ovarectimized female mice. Moreover, this enzyme was elevated in activity by the administration of high (nonphysiological) levels of progesterone. Development studies showed that the liver and kidney AHD-Cy isozyme exhibited low activities in late-stage fetal and neonatal mice and reached adult levels by approximately 6 weeks of age.