Purification and Characterization of the Heat-Stable Factors Essential for the Conversion of Lignoceric Acid to Cerebronic Acid and Glutamic Acid: Identification of N-Acetyl-l-Aspartic Acid |
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| Authors: | Hidenari Shigematsu,Nobuyuki Okamura,Hiroshi Shimeno,Yasuo Kishimoto,Lou-sing Kan,&dagger ,Catherine Fenselau&Dagger |
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| Affiliation: | John F. Kennedy Institute, Johns Hopkins University, Baltimore, Maryland, U.S.A., Department of Neurology, Johns Hopkins University, Baltimore, Maryland, U.S.A.;Department of Pharmacology and Experimental Therapeutics, Johns Hopkins University, Baltimore, Maryland, U.S.A.;School of Medicine and Department of Biochemistry, Division of Biophysics, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland, U.S.A. |
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| Abstract: | Abstract: The conversion of lignoceric acid to cerebronic acid, ceramides, cerebrosides, and glutamic acid is catalyzed by a rat brain particulate preparation. The heat-stable factor, prepared from calf cerebellum, together with the heat-labile factor, a pyridine nucleotide, and Mg2+ are essential to all of these metabolic pathways. Our previous work showed that the heat-stable factor is composed of at least two components, HSF-1 and HSF-2, and identified HSF-2 as d -glucose-6-phosphate. In the current investigation, HSF-1 was further purified and found to be N -acetyl- l -aspartic acid. In addition, it was discovered that a third component, HSF-3, is also required for heat-stable factor activity. A reconstituted system composed of N -acetylaspartic acid, glucose-6-phosphate, and HSF-3 fully replaced the heat-stable factor essential for the conversion of lignoceric acid to cerebronic acid and glutamic acid. The reconstituted heat-stable factor did not show the initial time lag always observed with the crude heat-stable factor. |
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| Keywords: | Lignoceric acid α-hydroxylation Cerebronic acid synthesis Heat-stable factor Glucose-6-phosphate N-Acetylaspartic acid Glutamic acid formation |
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