[Study of the secondary structure of L-asparaginase over a broad range of pH values].

Conformation of L-asparaginase from E. coli had been studied by spectropolarimetry methods (CD and ORD) in pH region from 2.5 to 12.5. Results were correlated with the change in enzyme activity. It was shown that the secondary structure of the enzyme degraded when pH was smaller than 5 and larger than 10. Degradation was accompanied by the dissociation of the agregative form on individual subunits. In pH region form 5 to 10 the secondary structure of L-asparaginase does not change. Secondary structure parameters of L-asparaginase calculated from the known aminoacid consequence by means of two independent theoretical methods are in satisfactory agreement with results of CD and ORD analysis spectra. It is proposed that there exists a hydrofobic slit into which the decapeptid containing serine from the L-asparaginase active site is plunged.