Described herein are compounds and compositions characterized, in certain embodiments, by conjugation of various groups, such as lipophilic groups, to an amino or amide group of an amino acid, a linear or cyclic peptide, a linear or cyclic polypeptide, or structural isomer thereof, to provide compounds of the present invention, collectively referred to herein as “APPLs”. Such APPLs are deemed useful for a variety of applications, such as, for example, improved nucleotide delivery. Exemplary APPLs include, but are not limited to, compounds of Formula (I), (II), (III), (IV), (V), and (VI), and salts thereof, as described herein: wherein m, n, p, R′, R1, R2, R3, R4, R5, R8, Z, W, Y, and Z are as defined herein.