Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aspartate aminotransferase (L-aspartate : 2-oxoglutarate aminotransferase, EC 2.6.1.1) has been covalently bound to chemically activated collagen films. This enzyme had never previously been coupled to any other solid support. The coupling method, including acyl azide formation on the carrier, allowed coupling of many other enzymes. A systematic study of coupling conditions has been performed; influence of time of coupling and of concentration of coupling solution on the enzymatic activity retained on the film. Coupling solutions could be used for several successive couplings. To determine the yield of binding, N-[14C] ethylmaleimide-labelled enzyme was prepared fully active and bound to collagen films. After lyophilisation the film retained most of its activity when stored in buffer and the half-life of the enzymatic film was about ten months. pH Dependence and activation energy were about the same for soluble and coupled enzyme. Coupling protects against thermal denaturation and increases the stability of the enzyme; the enzymatic film could be used repeatedly. Kinetics were somewhat modified in the coupled enzyme as compared to the enzyme in solution. Glutamate appeared more available while oxaloacetate seemed to be limiting. These modifications might be due to the proteic support itself. The enzymatic films also revealed themselves as a good tool for industrial or clinical purposes as well as for studying the mechanism of enzyme action.
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PMID:Surface-bound aspartate aminotransferase on collagen films. Compared properties with native enzyme. 23 97

Dependence of the enzymatic reaction rate V. catalyzed by aspartate aminotransferase, on concentration of standard human blood serum Moni-trol I ("Dade", Switzerland) was studied. In the range of moderate dilutions, which did not exceed 1.3-times, the V value altered in accordance with the blood serum concentration C. Under conditions of extensive dilutions dependence of V on blood serum concentration became complicated. The non-linear type of V dependence on blood serum concentration appears to be due to deaggregation of the enzyme molecules with formation of more active fragments as a result of blood serum dilution. Two parameters should be used for characteristics of blood serum aspartate aminotransferase activity: the enzymatic activity of undiluted blood serum as well as the ratio between specific activities of the enzyme in an associated from and the products of its dissociation, i.e. when C-1 and C-0, respectively.
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PMID:[Aspartate aminotransferase activity as dependent on the degree of serum dilution]. 381 Dec 89