103476-89-7 (HEMISULFATE SALT) 24365-47-7 (FREE PEPTIDE (ALT)) 55123-66-5 (FREE PEPTIDE(PREFERRED)) AIDS-006471 AIDS006471 Ac-Leu-Leu-Arg-H L-Leucinamide, N-acetyl-L-leucyl-N-[(1S)-4-[(aminoiminomethyl)amino]-1-formylbutyl]- Leupeptin N-Acetyl-L-leucyl-L-leucyl-L-arginine, aldehyde deriv.