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Aldehyde Dehydrogenases in Rat Brain. Subcellular Distribution and Properties
Author(s) -
Pettersson Hans,
Tottmar Olof
Publication year - 1982
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1982.tb08653.x
Subject(s) - acetaldehyde , aldehyde dehydrogenase , biochemistry , chemistry , intermembrane space , succinate dehydrogenase , monoamine oxidase , enzyme , ethanol , bacterial outer membrane , escherichia coli , gene
Kinetic studies suggested the presence of several forms of NAD‐dependent aldehyde dehydrogenase (ALDH) in rat brain. A subcellular distribution study showed that low‐ and high‐ K m activities with acetaldehyde as well as the substrate‐specific enzyme succinate semialdehyde dehydrogenase were located mainly in the mitochondrial compartment. The low‐ K m activity was also present in the cytosol (<20%). The low‐ K m activity in the homogenate was only 10–15% of the total activity with acetaldehyde as the substrate. Two K m values were obtained with both acetaldehyde (0.2 and 2000 μ m ) and 3,4‐dihydroxyphenylacetaldehyde (DOPAL) (0.3 and 31 μ m ), and one K m value with succinate semialdehyde (5 μ m ). The main part of the aldehyde dehydrogenase activities with acetaldehyde, DOPAL, and succinate semialdehyde, but only little activity of the marker enzyme for the outer membrane (monoamine oxidase, MAO), was released from a purified mitochondrial fraction subjected to sonication. Only small amounts of the ALDH activities were released from mitochondria subjected to swelling in a hypotonic buffer, whereas the main part of the marker enzyme for the intermembrane space (adenylate kinase) was released. These results indicate that the ALDH activities with acetaldehyde, DOPAL and succinate semialdehyde are located in the matrix compartment. The low‐ K m activity with acetaldehyde and DOPAL, but not the high‐ K m activities and succinate semialdehyde dehydrogenase, was markedly stimulated by Mg 2+ and Ca 2+ in phosphate buffer. The low‐ and high‐ K m activities with acetaldehyde showed different pH optima in pyrophosphate buffer.