THE PURIFICATION OF AN ALKALINE PROTEINASE OBTAINED FROM ASPERGILLUS ORYZAE AND THE DETERMINATION OF ITS PROPERTIES.
Abstract
Aspergillopeptidase B, an alkaline protease in A, oryzae extracts, was obtained in highly purified form by conventional fractionation techniques. The enzyme is a compact protein of 17,900 m.w. with a neutral isoelectric point. It contains no S-containing amino acids, phosphorus or metal ions. It is composed of a single polypeptide chain with N-terminal glycine and C-terminal alanine residues. The protease activity toward casein is optimal at pH 10.3, and esterase activity is optimal at lower pH ranges. It is inhibited by Hg(II) and Ag(I). The enzyme also reacts with diisopropylfluoro- phosphate yielding an inactive DP-protein containing one atom of P per mole of protein. Kinetic and thermodynamic measurements of the denaturation of the enzyme by heat, urea, and guanidine hydrochloride were made. The specificity of the action of this enzyme differs from that of other known proteinases. Although it fails to attach any of the synthetic peptides thus far tested, it splits the Glu-Asn, the Cys-Ser, the Tyr-Gln bonds of the oxidized A chain of insulin, and the Leu-Tyr bond of the oxidized B chain of insulin. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 13, 1966
- Accession Number
- AD0482987
Entities
People
- George Kalnitsky
Organizations
- University of Iowa