Purification and characterization of new anti-adrenocorticotropin rabbit neutrophil peptides (defensins).
Neutrophil peptides (NPs, defensins), which consist of approximately 30 amino acids with a highly conserved backbone of six Cys residues, possess several biological activities, such as antimicrobial, antiviral, cytotoxic, and anti-adrenocorticotropin (corticostatic) activity in vitro. In the rabbit, six NPs, i.e., NP-1, -2, -3A, -3B, -4, and -5, have been isolated, among them, NP-3A has the most potent corticostatic activity, which involves the inhibition of adrenocorticotropin-stimulated corticosterone synthesis in adrenal cells. Using a sensitive radioimmunoassay for NP-3A and reverse-phase HPLC, we found a novel component in rabbit tissue extracts with NP-3A-like immuno-reactivity. We further purified and characterized the component and found two novel peptides. One of these peptides, designated NP-6, has an amino acid sequence identical to that of NP-3A except for three amino acids, i.e. Leu11, Phe13, and Gln15, in the central portion of the sequence. The other has a sequence corresponding to that of NP-6 except that the N-terminal Gly was deleted and is thus named des-G1-NP-6. Using chemically synthesized NP-6 and des-G1-NP-6, we measured their putative corticostatic activities by a dispersed rat adrenal cell bioassay. NP-6 showed corticostatic activity comparable to that of NP-3A while des-G1-NP-6 showed weak activity. These findings are also compatible with the notion that the N-terminal Gly, but not the central portion, is important for the anti-adrenocorticotropin activity of the NPs.
Life Science Research Center, Nippon Steel Corporation, Kawasaki, Japan.
N
N
Fuse
Y
Y
Hayashi
J
J
Fukata
T
T
Tominaga
O
O
Ebisui
Y
Y
Satoh
T
T
Isohara
I
I
Uno
H
H
Imura
D000324:Adrenocorticotropic Hormone / Q000037:antagonists & inhibitors*; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001798:Blood Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D023082:Defensins; D008297:Male; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000737:chemistry*; D011817:Rabbits; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D017386:Sequence Homology, Amino Acid; D023084:alpha-Defensins
D000596:Amino Acids; D001798:Blood Proteins; D023082:Defensins; D023084:alpha-Defensins; C406566:defensin NP-3a; D000324:Adrenocorticotropic Hormone