Brain Sugar

Fructose, also known as fruit sugar, is a hexose found in many fruits and vegetables and is a major component of honey. Galactose, also known as brain sugar, is a hexose usually foimd combined with other monosaccharides in substances such as lactose (see next section). Galactose is also present within the brain and nervous system of most animals. 

Molecular weight 180.16 (180.06) Synonyna Cerebroae brain sugar... 

D-galactose, C HiiOe. Crystallizes in the pyranose form m.p. 1I8-120 C (monohydrate), 165-5" C (anhydrous). An isomer of glucose which is fairly widely distributed in plants. It is a constituent of raffinose and slachyose, of hemicelluloses, of pectin, of gums and mucilages, and of some glycosides. In animals it forms half the lactose molecule and is the sugar found in the brain. Chemically it is very similar to glucose. It has the structure... 

Perez, N., Sugar, J., Chatya, S., Johnson, G., Merril, C., Bierer, L., Perl, D., Haroutunian, V., Wallace, W. (1991). Increased synthesis and accumulation of heat shock proteins in Alzheimer s disease Brain Res. Mol. Brain Res. 11,249-254. 

As the name implies, the odor of urine in maple syrup urine disease (brancbed-chain ketonuria) suggests maple symp or burnt sugar. The biochemical defect involves the a-keto acid decarboxylase complex (reaction 2, Figure 30-19). Plasma and urinary levels of leucine, isoleucine, valine, a-keto acids, and a-hydroxy acids (reduced a-keto acids) are elevated. The mechanism of toxicity is unknown. Early diagnosis, especially prior to 1 week of age, employs enzymatic analysis. Prompt replacement of dietary protein by an amino acid mixture that lacks leucine, isoleucine, and valine averts brain damage and early mortality. 

Doege, H., et al. Activity and genomic organization of human glucose transporter 9 (GLUT9), a novel member of the family of sugar-transport facilitators predominantly expressed in brain and leucocytes. Biochem. J. 2000, 350, 771-776. 

ACE has been used to characterize protein-sugar interactions,45 DNA binding to an anti-DNA monoclonal antibody,46 antibody-antigen47 antisteroidal inflammatory drugs,48 and prion protein in sheep brain preparations.49... 

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