Fast atom bombardment mass spectrometric investigation of in vitro degradation within the disulfide-linked core of atrial natriuretic factor.
The use of high-performance liquid chromatography and fast atom bombardment mass spectrometry are shown to be an efficient combination for investigating protease-mediated digestion of synthetic analogs of the peptide hormone ANF (atrial natriuretic factor). As examples of the reported methodology, rANF5-23-NH2 and rANF7-23-NH2 were digested with the endopeptidase thermolysin. These truncated analogs were selected to investigate metabolism within the disulfide-linked core of ANF, particularly at the Cys7-Phe8 bond. While this position was the site of initial hydrolysis for rANF5-23-NH2 (t1/2 = 0.5 min), the Cys7-Phe8 bond remained intact for all observed degradation products of rANF7-23-NH2 (t1/2 = 16 min). These findings suggest that improved stability towards endopeptidase-mediated core hydrolysis may be conferred to analogs of ANF by removal of the first six residues from the N-terminus.
Chen
T M
TM
Merrell Dow Research Institute, Cincinnati, Ohio 45215.
Ackermann
B L
BL
Coutant
J E
JE
Berman
J M
JM
Pelton
J T
JT
D000595:Amino Acid Sequence; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000138:chemical synthesis / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D066298:In Vitro Techniques; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism; D051381:Rats; D013820:Thermolysin
D010446:Peptide Fragments; C059392:atrial natriuretic factor (7-23)amide; C059391:atrial natriuretic factor (5-23)amide; D009320:Atrial Natriuretic Factor; D013820:Thermolysin