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M Koivusalo

Publications and source records attributed to M Koivusalo.

At least 37 records · Page 2Linked to original sources
PubMed1992

Regional distribution of low-Km mitochondrial aldehyde dehydrogenase in the rat central nervous system.

To clarify the regional capacity of the brain to oxidize biogenic aldehydes and ethanol-derived acetaldehyde, a quantitative immunohistochemical study of the microregional and cellular expression of low Km mitochondrial aldehyde dehydrogenase (mALDH; EC 1.2.1.3) in the rat central nervous system was undertaken, using antiserum raised in rabbit against low-Km aldehyde dehydrogenase purified from rat liver mitochondria. mALDH-specific immunoreactivity (IR) was observed to various extent in the majority of structures in all brain and spinal cord areas. Staining was strong in the extranuclear cytoplasm of neuronal and glial cell bodies but less pronounced in their processes and terminals, the conducting tracts, white matter and neuropile and in blood vessels. Immunostaining density was 2 to 3 times higher in neuronal perikarya as compared with neuropile. mALDH-positive neurons were found in all brain regions, being strongest in the inferior olive and hippocampus stratum pyramidale and weakest in substantia nigra. The percentage of morphologically identifiable ALDH-positive neurons ranged from 40% in the arcuate hypothalamic nucleus to 88% in the cerebellar Purkinje cells. A comparison of the heterogeneous expression of mALDH in various rat CNS regions and cells, as observed in the present study, with the corresponding previously published distributions of the potential acetaldehyde-producing enzymes ADH and cytochrome P450 2E1 indicates major differences, which may help in understanding potential acetaldehyde-mediated CNS effects of ethanol. Knowledge of the regional distribution of high-affinity aldehyde dehydrogenase should also throw light on the neurophysiological role of local regulation of the metabolism of biogenic aldehydes in the brain.

Aldehyde Dehydrogenase↗
PubMed1989

Evidence for the identity of glutathione-dependent formaldehyde dehydrogenase and class III alcohol dehydrogenase.

Formaldehyde dehydrogenase (EC 1.2.1.1) is a widely occurring enzyme which catalyzes the oxidation of S-hydroxymethylglutathione, formed from formaldehyde and glutathione, into S-formyglutathione in the presence of NAD. We determined the amino acid sequences for 5 tryptic peptides (containing altogether 57 amino acids) from electrophoretically homogeneous rat liver formaldehyde dehydrogenase and found that they all were exactly homologous to the sequence of rat liver class III alcohol dehydrogenase (ADH-2). Formaldehyde dehydrogenase was found to be able at high pH values to catalyze the NAD-dependent oxidation of long-chain aliphatic alcohols like n-octanol and 12-hydroxydodecanoate but ethanol was used only at very high substrate concentrations and pyrazole was not inhibitory. The amino acid sequence homology and identical structural and kinetic properties indicate that formaldehyde dehydrogenase and the mammalian class III alcohol dehydrogenases are identical enzymes.

Alcohol Dehydrogenase↗
PubMed1989

Isolation of glyoxalase II from two different compartments of rat liver mitochondria. Kinetic and immunochemical characterization of the enzymes.

Two separate pools of glyoxalase II were demonstrated in rat liver mitochondria, one in the intermembrane space and the other in the matrix. The enzyme was purified from both sources by affinity chromatography on S-(carbobenzoxy)glutathione-Affi-Gel 40. From both crude and purified preparations polyacrylamide gel-electrophoresis resolved multiple forms of glyoxalase II, two from the intermembrane space and five from the matrix. Among the thioesters of glutathione tested as substrates, S-D-lactoylglutathione was hydrolyzed most efficiently by the enzymes from both sources. Significant differences were observed in the specificities between the intermembrane space and matrix enzymes with S-acetoacetylglutathione, S-acetylglutathione, S-propionylglutathione and S-succinylglutathione as substrates. Pure glyoxalase II from rat liver cytosol was chemically polymerized and used as antigen. Antibodies were raised in rabbits and the antiserum was used for comparison of the two purified mitochondrial enzymes with cytosolic glyoxalase II by immunoblotting. The enzyme purified from the intermembrane space cross-reacted with the antiserum, but the matrix glyoxalase II did not. The results give evidence for the presence in rat liver mitochondria of two species of glyoxalase II with differing characteristics. Only the enzyme from the intermembrane space appears to resemble the cytosolic glyoxalase II forms.

Animals↗
PubMed1989

Placental alcohol metabolism in chronic alcohol abuse.

The activities of aldehyde dehydrogenase (ALDH; EC 1.2.1.3) and alcohol dehydrogenase (ADH; EC 1.1.1.1) were measured in term placentas of 13 alcoholic women and 16 matched controls. With acetaldehyde 8 mmol/l as substrate, the ALDH activity was 29.1 +/- 12.2 and 34.4 +/- 15.3 mU/g of wet weight (mean +/- SD; p greater than 0.4) for alcoholics and controls, respectively. With 50 mumol of acetaldehyde, ALDH activity was undetectable in both groups. No ADH activity could be detected in the placentas. The weights of placentas and newborns were significantly lower in the alcoholic group (placentas: 526 +/- 116 vs. 653 +/- 77 g, p less than 0.005; newborns 2,878 +/- 417 vs. 3,595 +/- 346 g, p less than 0.001). The results suggest that in chronic alcohol abuse, the placenta plays a negligible role in the metabolism of ethanol and acetaldehyde.

Acetaldehyde↗
PubMed1988

Demonstration of glyoxalase II in rat liver mitochondria. Partial purification and occurrence in multiple forms.

Glyoxalase II (S-(2-hydroxyacyl)glutathione hydrolase, EC 3.1.2.6), which has been regarded as a cytosolic enzyme, was also found in rat liver mitochondria. The mitochondrial fraction contained about 10-15% of the total glyoxalase II activity in liver. The actual existence of the specific mitochondrial glyoxalase II was verified by showing that all of the activity of the crude mitochondrial pellet was still present in purified mitochondria prepared in a Ficoll gradient. Subfractionation of the mitochondria by digitonin treatment showed that 56% of the activity resided in the mitochondrial matrix and 19% in the intermembrane space. Partial purification of the enzyme (420-fold) was also achieved. Statistically significant differences were found in the substrate specificities of the mitochondrial and the cytosolic glyoxalase II. Electrophoresis and isoelectric focusing of either the crude mitochondrial extract or of the purified mitochondrial glyoxalase II resolved the enzyme activity into five forms with the respective pI values of 8.1, 7.5, 7.0, 6.85 and 6.6. Three of these forms (pI values 7.0-6.6) were exclusively mitochondrial, with no counterpart in the cytosol. The relative molecular mass of the partially purified enzyme, as estimated by Superose 12 gel chromatography, was 21,000. These results give evidence for the presence of mitochondrial glyoxalase II which is different from the cytosolic enzymes in several characteristics.

Animals↗
PubMed1987

Multiple forms of formaldehyde dehydrogenase from human red blood cells.

Red cell hemolysates from nonrelated Finns were analyzed by electrofocusing on polyacrylamide gel, and formaldehyde dehydrogenase (EC 1.2.1.1) was located by an activity-staining method. Three forms of the enzyme were constantly found for all the individuals studied but no variants were observed in this population (n = 217). Human liver also had three formaldehyde dehydrogenase forms with locations identical to those of the red cell formaldehyde dehydrogenase. Population genetic studies of formaldehyde dehydrogenase can easily be performed with red cell hemolysates with the techniques described here, and there is no need to use liver biopsy samples.

Aldehyde Oxidoreductases↗
PubMed1987

Aldehyde dehydrogenase activities and NAD+-dependent formaldehyde oxidation in perivenous and periportal hepatocytes: effect of induction by beta-naphthoflavone.

The acinar distribution of aldehyde oxidizing capacity was studied by direct assay of rat hepatocytes prepared from either the periportal or the perivenous region. No significant zonation of low- or high-Km aldehyde dehydrogenase or formaldehyde oxidation was discerned. The induction of cytosolic aldehyde dehydrogenase by pretreatment with beta-naphthoflavone occurred to the same extent in both periportal and perivenous hepatocytes.

Aldehyde Dehydrogenase↗
PubMed1982

Induction of rat liver cytoplasmic aldehyde dehydrogenase by phenobarbital and polycyclic hydrocarbons. Comparison of different isoenzyme types.

The induction of rat liver cytoplasmic aldehyde dehydrogenase by some xenobiotics and phenobarbital are compared. An acute and a chronic treatment with polycyclic hydrocarbons and with TCDD produce a similar pattern of induced enzymes in isoelectric focusing. The result is clearly different from induction with phenobarbital in the genetically selected rat strain. Another main activity in cytoplasm consists of three different isoenzyme patterns which evidently are normal enzyme types. The induced enzyme of liver cytoplasm after chronic AAF-treatment was purified to homogeneity. The enzyme had a molecular weight of 90000 and a subunit molecular weight of 45000. It had Km-values in the millimolar range for aliphatic aldehydes and in the micromolar range for aromatic aldehydes. Both NAD and NADP were coenzymes of the purified aldehyde dehydrogenase.

Aldehyde Dehydrogenase↗