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21.
Faisal Tanvir R. Adouni Malek Dhaher Yasin Y. 《Biomechanics and modeling in mechanobiology》2023,22(1):43-56
Biomechanics and Modeling in Mechanobiology - A characteristic feature of arthritic diseases is cartilage extracellular matrix (ECM) degradation, often orchestrated by the overexpression of matrix... 相似文献
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Phosphatase Activity Toward Abnormally Phosphorylated τ: Decrease in Alzheimer Disease Brain 总被引:1,自引:0,他引:1
Cheng-Xin Gong Sadia Shaikh Jian-Zhi Wang Tanweer Zaidi Inge Grundke-Iqbal Khalid Iqbal 《Journal of neurochemistry》1995,65(2):732-738
Abstract: Microtubule-associated protein τ is abnormally hyperphosphorylated and aggregated in affected neurons of Alzheimer disease brain. This hyperphosphorylated τ can be dephosphorylated at some of the abnormal phosphorylated sites by purified protein phosphatase-1, 2A, and 2B in vitro. In the present study, we have developed an assay to measure protein phosphatase activity toward τ-1 sites (Ser199 /Ser202 ) using the hyperphosphorylated τ isolated from Alzheimer disease brain as substrate. Using this assay, we have identified that in normal brain, protein phosphatase-2A and 2B and, to a lesser extent, 1 are involved in the dephosphorylation of τ. The K m values of dephosphorylation of the hyperphosphorylated τ by protein phosphatase-2A and 2B are similar. The τ phosphatase activity is decreased by ∼30% in brain of Alzheimer disease patients compared with those of age-matched controls. These findings suggest that a defect of protein phosphatase could be the cause of the abnormal hyperphosphorylation of τ in Alzheimer disease. 相似文献
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Molecular and Cellular Biochemistry - The excitatory amino acids (EAA), L-glutamate and L-aspartate were initially advanced as excitatory neurotransmitters some 30 years ago but in the past few... 相似文献
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R W Newton M C Browning J Iqbal N Piercy D G Adamson 《BMJ (Clinical research ed.)》1978,1(6105):73-74
A man who had worked for 16 years in the manufacture of a potent corticosteroid was found to be suffering from chronic adrenocortical insufficiency attributed to chronic absorption of the glucocorticoid. Eleven other symptom-free workers were therefore screened. Two of these workers, like the first patient, gave grossly abnormal responses to the Synacthen (tetracosactrin) test; one had been employed for only seven months. All 12 men had facial plethora, suggesting absorption of the drug in spite of their having adhered to the safety precautions. All workers manufacturing potent steroids should therfore be screened regularly by measurement of their plasma cortisol concentrations and should be moved regularly to processing other drugs. 相似文献
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Mycelium of Fusarium oxysporum grown on a glucose-containing medium lacked fructosyl transferase and invertase activities. Synthesis of fructosyl t 相似文献
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Ketan Shah Iqbal Mehdi A. W. Khan V. C. Vora 《Applied microbiology and biotechnology》1980,10(1-2):167-169
Summary
Arthrobacter
simplex, Serratia
marcescens, Fusarium and Mycobacterium were tested for their ability to transform phytosterol to Androsta 1, 4 diene 3, 17 dione (ADD). Arthrobacter
simplex ATCC 6946 was found to be more efficient than the other species tested. 相似文献
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This report describes a simple method to measure the activity of dihydrofolate reductase using the substrate [3H]dihydrofolate, which is generated by preincubation of [3H]folic acid for 10 min with dithionite before the enzymatic reaction. The procedure then measures the direct reduction of [3H]dihydrofolate to [3H]tetrahydrofolate by coprecipitating the unreduced substrate with excess unlabeled folic acid and acidified zinc sulfate. The advantage of this method is that [3H]dihydrofolate, which is not commercially available, can be generated from high specific activity [3H]folic acid, which is commercially available, immediately before initiating the enzymatic reaction. By this modification, the two important advantages of radioenzymatic assays for dihydrofolate reductase can be more easily exploited; namely, increased sensitivity because much less substrate need be used, and the ability to measure enzyme activity in crude tissue preparations without interference by precipitating proteins or nucleotide oxidases. 相似文献