Involved in cyanogenesis, the release of HCN from injured tissues. Is involved in the catabolism of the cyanogenic glycoside dhurrin. (S)-4-hydroxymandelonitrile = 4-hydroxybenzaldehyde + hydrogen cyanide Heterotetramer of two A and two B chains. The A and B chains are linked by a disulfide bond. Primary leaves of seedlings. The N-terminus of chain A is blocked. Belongs to the peptidase S10 family.