the mr 37 000 d-alanyl-d-alanine peptidase excreted by streptomyces r61 and the mr 53 000 d-alanyl-d-alanine peptidase excreted by actinomadura r39 are both characterized by a very uneven distribution of the basic ( arg + lys ) amino acid residues .
C0001898
alanine
C0002520
amino acid