Glycerol deficiency

The average functionality of nonstoichiometric mixtures has been deduced [Pinner, 1956] as being equal to twice the total number of functional groups that are not in excess divided by the total number of all molecules present. This simply takes into account the fact that the extent of polymerization (and crosslinking, if it can occur) depends on the deficient reactant. The excess of the other reactant is not useful in fact, it results in a lowering of the functionality of the system. For the above nonstoichiometric mixture of 1 mol of glycerol and 5 mol of phthalic acid, the /avg value is correctly calculated as 6/6 or 1.00. This low value of /avg is indicative of the low degree of polymerization that will occur in the system. 

Specimen contamination may not be immediately apparent on visual inspection. A large peak of glycerol, especially in a female newborn or infant, should be considered an artifact at first and verified by a repeat specimen before raising the possibility of glycerol kinase deficiency. Medium- and long-chain monocarboxylic fatty acids (Cio-Ci8) could be very prominent peaks in a urine profile following contamination... 

Disorders of glycerol metabolism include glycerol kinase (GK) deficiency (GKD) and glycerol intolerance syndrome (GIS). Of these, only GKD is well characterized and has a defined biochemical defect [1]. 

Guggenheim MA, McCabe ER, Roig M, Goodman SI, Lum GM, Bullen WW, Ringel SP (1980) Glycerol kinase deficiency with neuromuscular, skeletal, and adrenal abnormalities. Ann Neurol 7 441-449... 

McCabe ER, Fennessey PV, Guggenheim MA, Miles BS, Bullen WW, Sceats DJ, Goodman SI (1977) Human glycerol kinase deficiency with hyperglycerolemia and glyceroluria. Biochem Biophys Res Commun 78 1327-1333... 

McCabe ER, Sadava D, Bullen WW, McKelvey HA, Seltzer WK, Rose Cl (1982) Human glycerol kinase deficiency enzyme kinetics and fibroblast hybridization. J Inherit Metab Dis... 

Sjarif DR, Hellerud C, van Amstel JK, Kleijer WJ, Sperl W, Lacombe D, Sass JO, Beemer FA, Duran M, Poll-The (2004) Glycerol kinase deficiency residual activity explained by reduced transcription and enzyme conformation. Eur J Hum Genet 12 424-432... 

Stanczak CM, Chen Z, Zhang YH, Nelson SF, McCabe ERB (2007) Deletion mapping in Xp21 for patients with complex glycerol kinase deficiency using SNP mapping arrays. Hum Mutat 28 235-242... 

Apo C-ll activates lipoprotein lipase, which degrades the chylomicron s triacylglycerol to fatty acids and glycerol. The fatty acids that are released are stored (in the adipose) or used for energy (by the muscle). The glycerol is metabolized by the liver. Patients with a deficiency of lipoprotein lipase or apo C-ll show a dramatic accumulation of chylomicrons in the plasma (type 1 hyperlipoproteinemia, familial lipoprotein lipase deficiency, or hypertriacylglycerolemia)... 

Adrenal hypoplasia Glycerol kinase deficiency Chronic granulomatous disease Retinitis pigmentosa-3 Duchenne muscular dystrophy Becker muscular dystrophy... 

The final proof of the gluconeogenic function of FDPase came from observations with mutants lacking this enzyme. Bacterial strains deficient in a specific FDPase (17) were found to be incapable of growth on compounds such as glycerol, acetate, or succinate. Similar metabolic defects have recently been described in man (18, 19). Children with... 

Fraenkel et al. (17), who isolated mutant strains which had lost the ability to grow on glycerol, succinate, or acetate but grew normally on hexoses or pentoses. These organisms were shown to be deficient in a specific FDPase, which could be distinguished from the nonspecific acid hexosephosphatase present in both mutant or wild-type strains by the fact that the latter was present in the periplasmic space (86) and did not require a divalent metal cation. The properties of the specific FDPase were confirmed with a partially purified preparation (87) the E. coli enzyme was shown to be highly specific for FDP and to be active with very low concentrations of this substance. The requirement for a divalent cation was satisfied by Mg2+, which was far more effective than Mn2+ other divalent cations were either inactive or inhibitory. The partially purified enzyme showed optimum activity at pH 7.8, with very little activity below pH 7 or above pH 9. The enzyme resembled mammalian and Candida FDPases in its sensitivity to low concentrations of AMP it was approximately 50% inhibited at an AMP concentration of 2.5 X 10-° M. 

Glycerol is effective in enhancing hydration of the stratum corneum in dry skin.29 Recently it has been shown that the epidermal water/glycerol transporter aquaporin-3 in deficient mice leads to severely impaired stratum corneum hydration.9 In these mice, stratum corneum glycerol content was reduced threefold. And it was shown that glycerol replacement corrects the defects in these mice.30 However, it has not yet been published whether changes in the aquaporin-3 transporter occur in human dry skin or in aged dry skin. 

Hara, M. and Verkman, A.S., Glycerol replacement corrects defective skin hydration, elasticity, and barrie function in aquaporin-3-deficient mice, Proc. Natl. Acad. Sci. USA, 100, 7360-7365, 2003. 

Hara, M., Ma, T., and Verkman, A. Selectively reduced glycerol in skin of Aquaporin-3-deficient mice may account for impaired skin hydration, elasticity and barrier recovery,./. Biol. Chem., 277, 44616, 2002. 

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