Glycolipid hydrolase

TABLE II. p-Nitrophenylgalactosidase and Glycolipid Hydrolase Activities in Aqueous Extracts of Acetone Powders of Human Cerebral Gray Matter ... 

The quantification of activator proteins is generally based on their capability to stimulate in vitro the degradation of glycolipids by the corresponding hydrolases. The relation between concentration of activator in the assay mixture and resulting reaction rate is linear only within certain limits that depend not only on the reaction catalyzed and on the type of activator protein but also on the precise assay conditions. 

Those activator proteins that promote the hydrolysis of glycolipid substrates by water-soluble hydrolases, namely the Gm2 activator and the sulfatide activator, seem to act by similar mechanisms they bind the glycolipid and extract it from the membrane to form a water-soluble complex that is the true substrate for the enzyme. Accordingly, the reaction rate depends on the concentration of the activator-lipid complex, with Michaelis-Menten-type saturation kinetics (Conzelmann and Sandhoff, 1979). Such a saturation curve is at no point exactly linear, but for practical purposes sufficient linearity can be assumed at activator concentrations below the value of the enzyme for the respective activator-lipid complex as substrate. 

Glycolipid Sulphate Sulphatases.—Proteins of low molecular weight from secondary lysosomes activated a number of sphingolipid hydrolases, including cerebroside sulphatase (E.C. 3.1.6.8). ... 

A review of the chemistry and the biochemical control of hereditary glycolipid diseases refers to the deficiencies of glycoside hydrolases in these diseases. ... 

The consistent binding of this glycolipid by H. pylori [18] and many other bacteria [43] is still an enigma, because this glycolipid has not been found in human stomach or other human tissues [51]. However, it exists substituted with NeuAc or Fuc and potential microbial hydrolases may expose the binding epitope. Alternatively, this represents a crossbinding with some yet unidentified epitope. 

Our interest in complex lipids in neoplastic cells was initiated through an investigation of glycolipid metabolism in human leukocytes. It was observed that white blood cells from normal individuals contain several sphingolipid hydrolases. The activity of these enzymes in leukocytes parallels that in systemic organs and tissues. For example, the activity of glucocerebrosidase (reaction 1) is diminished in patients with... 

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