1,720,983 research outputs found
Heterologous enzyme-enzyme complex between D-fructose-1,6-bisphosphate aldolase and triosephosphate isomerase from Ceratitis capitata.
No full text
A collagen film for microdetermination of collagenase activity.
No full textA simple, rapid, sensitive, and specific film assay for collagenase activity employing a glass-supported, reconstituted collagen gel is described. Digestion of the collagen film results in sharply defined zones of lysis detectable by staining with Coomassie blue. The assay is semiquantitative and suitable for micro enzyme determination in biological fluids
Circular-dichroism study of the interaction of aspartate-aminotransferase isoenzymes with a coenzyme analog.
No full textThe interaction between a coenzyme derivative, 4'-N-(2,4-dinitro-5-fluorophenyl)-pyridoxamine 5'-phosphate, and the apoenzyme of cytoplasmic and mitochondrial aspartate aminotransferase, was studied by circular dichroism. The specific complexes initially formed were characterized by their circular dichroic spectra. The spectra indicate that the complex is very probably the same for the two isoenzymes. In contrast the spectra recorded during further reaction, in agreement with previous results, monitor different reaction paths and characterize the irreversible labeling at the active site of the cytoplasmic enzyme and regeneration of pyridoxal 5'-phosphate in the mitochondrial enzyme. By following circular dichroic changes in the mitochondrial enzyme, initial kinetic characterization of the cleavage of 4'-N-(2,4-dinitro-5-fluorophenyl)-pyridoxamine 5'-phosphate to form pyridoxal 5'-phosphate at the active site, is provided
Collagenase activity in human synovial fluids from joint diseases of diverse etiology.
No full textThe content of collagenase in latent as well as in apparent active form has been determined in synovial fluids from 21 patients with rheumatoid arthritis, 16 with non-rheumatoid inflammatory joint diseases, and 15 with degenerative joint disease. Collagenase activity was measured before and after activation of the latent enzyme by NaSCN treatment. Before activation, collagenase activity was present in the synovial fluids from 1 case of rheumatoid arthritis, 3 cases of degenerative joint disease, and 1 case of Behçet's syndrome. An excess of inhibitor was present in inactive synovial fluids. The incidence of collagenolytic activity markedly increased after treatment with NaSCN. When NaSCN-dependent collagenolytic activity was present, its value was of the same order of magnitude in all patients regardless of disease type. The diagnostic value of the finding of collagenase activity in synovial fluid, and the physiological meaning of the enzyme with reference to joint diseases, are discussed
Kinetics of coupled reactions catalyzed by aspartate amino transferase and glutamate dehydrogenase
No full textPhysico-chemical evidence for the interaction between aldolase and glyceraldehyde-3-phosphate dehydrogenase.
No full textPolarization of fluorescence measurements of aldolase and D-glyceraldehyde-3-phosphate dehydrogenase labeled with fluorescein isothiocyanate have been used to detect the possible formation of a soluble complex between the proteins. The results suggest an interaction between aldolase and D-glyceraldehyde-3-phosphate dehydrogenase with an apparent dissociation constant 3 X 10(-7) M and an apparent stoichiometry of two aldolase tetramers bound per tetramer of D-glyceraldehyde-3-phosphate dehydrogenase
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