Activator deficiency

Deficiency of essential amino acid precursors in the diet can cause a dysregulation of neurotransmitter activity (e.g, L-tryptophan deficiency causes a decrease in 5-HT and melatonin synthesis and activity). Deficiency in essential fatty acids (e.g, omega-3 fatty acids) can cause a dysregulation of neurottansmitter... 

Wolf B, Secor McVoy J (1983) A sensitive radioassay for biotinidase activity deficient activity in tissues of serum biotinidase-deficient individuals. Clin Chim Acta 135 275-281... 

O. Macheleidt, T. Kolter, K. Sandhoff, Sphingolipid activator deficiencies and Niemann-Pick Type C,... 

Children with profound biotinidase activity have less than 10% of mean normal serum enzyme activity. Deficient biotinidase activity has also been demonstrated in extracts of leukocytes and fibroblasts. At least one patient was shown to have deficient biotinidase activity in his liver. More than 300 symptomatic individuals have been reported with biotinidase deficiency. The parents of these children usually have serum enzyme activities intermediate between those of the patients and those of normal individuals. 

Tay-Sachs disease. A member of a family of disorders identified as the Gm2 gangliosidoses. As neural cell membranes are enriched in Gm2 gangliosides, the inability to degrade this class of sphingolipid resnlts in neural cell death. In addition to Tay-Sachs disease the family includes the Sandhoff diseases and the Gm2 activator deficiencies. Tay-Sachs disease resnlts from defects in the HEXA gene encoding the a-subunit of /3-hexosaminidase. 

Mouse models are available for Tay-Sachs disease (a-chain deficiency), Sandhoff disease (p-chain deficiency), and GM2-activator deficiency (T. Kolter, 1998). The mice have phenotypes that are only slightly different from human GM2 gangliosidoses. However, the severity and course of the disease differs, and this has been attributed to species differences in the sialidase activity of the mouse versus human. The mouse siali-dase accepts GM2 as a substrate (shown by the dashed arrow in Fig. 10) (K. Sango, 1995) and converts it to GA2, which cannot be further degraded since the responsible enzyme is also deficient. 

B6. Brandt, J. T., Plasminogen and tissue-type plasminogen activator deficiency as risk factors for thromboembolic disease. Arch. Pathol. Lab. Med. 126, 1376-1381 (2002). 

Hyperproteolytic activity of plasma may result from excessive amounts of plasminogen activator, deficiency in plasmin inhibitors, or appearance in plasma of proteolytic enzymes different from plasmin. Severe anoxia or shock releases large amounts of activators, and the rate of conversion of plasminogen to plasmin exceeds that of inhibition of plasmin activity. Patients with severe liver impairment (liver cirrhosis) may become unable to clear the activator from the blood, but in liver disease the levels of plasmin inhibitor may be low. 

The same epoxy system in the uncured state was studied by DSC/FT-IR as a function of activator/resin ratio. Excess activator (over stoichiometric amounts) generated a single peak exotherm on the DSC trace while the activator deficient system produced a double peak exotherm. The DSC cell was placed on an FT-IR microscope stage. While the epoxy system was being heated, infinred spectra were continually collected by micro-reflection/absorption. Spectra from the two systems were compared and interpreted to explain on a molecular level the noted differences in the DSC curves. The FT-IR data confirmed that these detected differences were due to changes in the rate of cure and reaction mechanism. 

A number of metal ions, such as iron, zinc, copper, magnesium, and selenium, play important roles in cellular activities. Deficiency in any metal ion delays wound healing. Apart from systemic intake of these metal ions in the diet, they can be administered through the topical use of appropriate wound dressings. 

Liu, Y. Hoffmann, A. Gringerg, A. Westphal, H. McDonald, M.P. Miller, K.M, Crawley, J.N. Sandhoff, K. Suzuki, K. Proia, R.L. Mouse Model of Gmz Activator Deficiency Manifests Cerebellar Pathology and Motor Impairment. Proc. Natl Acad ScL USA, 1997, 94, 8138-... 

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