The invention relates to peptides with biological activity against
infection having the amino acid sequence
Z.sub.1-LE-X.sub.1-IP-X.sub.2-X.sub.3-X.sub.4-P-X.sub.5-X.sub.6-X.sub.7-X-
.sub.8-X.sub.9-X.sub.10-K-X.sub.11-X.sub.12-X.sub.13-X.sub.14-X.sub.15-Z.s-
ub.2, wherein X.sub.1 is a lysine, alanine, or aspartic acid; X.sub.2 is a
cysteine, methionine or isoleucine; X.sub.3 is a serine, cysteine, lysine
or glycine; X.sub.4 is an isoleucine, alanine, phenylalanine or cysteine;
X.sub.5 is a proline, D-proline or a substituted L- or D-proline; X.sub.6
is a cysteine or glutamic acid; X.sub.7 is an amino acid with a
hydrophobic or an aromatic side chain or cysteine; X.sub.8 is an amino
acid with a hydrophobic or an aromatic side chain or cysteine; X.sub.9 is
an amino acid with an aromatic side chain; X.sub.10 is a glycine, alanine
or asparagine; X.sub.11 is a proline, aspartic acid,
octahydroindolyl-2-carboxylic acid or
D-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid; X.sub.12 is a
phenylalanine, alanine, glycine, glutamic acid or
D-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid; X.sub.13 is an amino
acid with a hydrophobic or an aromatic side chain; X.sub.14 is an amino
acid with a hydrophobic or an aromatic side chain; X.sub.15 is a
phenylalanine or deletion; Z.sub.1 is NH.sub.2 or a sequence of 1 to 10
amino acid residues; Z.sub.2 is COOH or a sequence of 1 to 10 amino acid
residues; and peptides which are fragments and/or covalently linked
oligomers and/or derivatives, especially amidated, alkylated, acylated,
sulfated, pegylated, phosphorylated and/or glycosylated derivatives, and
mutants thereof, and with the provisio that (a) if X.sub.12 is alanine,
glycine, glutamic acid, or D-1,2,3,4-tetrahydroisoquinoline-3-carboxylic
acid than X.sub.13, X.sub.14 and X.sub.15 are phenylalanine, valine and
phenylalanine respectively; and/or (b) if X.sub.12 is phenylalanine, than
X.sub.13, X.sub.14 and X.sub.15 are valine, phenylalanine and a deletion,
respectively; and (c) that there are at maximum two cysteine residues in
a peptide.
