[Complete primary structure of Bacillus thuringiensis extracellular ribonuclease].

Complete primary structure of an extracellular low molecular mass ribonuclease of Bacillus thuringiensis was determined using Edman degradation and mass-spectrometry analysis of individual peptides obtained after hydrolysis of the protein by cyanogen bromide and staphylococcal protease. The peptides were isolated and purified by HPLC and denaturing PAGE. The enzyme consists of 109 amino acid residues (Asp 8, Asn 6, Thr 6, Ser 10, Glu 3, Gln 1, Pro 3, Gly 9, Ala 12, Val 7, Ile 7, Leu 7, Tyr 7, Phe 4, His 1, Arg 10, Trp 3 and Lys 5) and has a molecular weight of 12182 Da. A single difference was detected between primary structures of the enzyme and an extracellular ribonuclease of B. intermedius.