Full-length and N-terminally truncated chicken intestinal diazepam-binding inhibitor. Purification, structural characterization and influence on insulin release.
Two forms of diazepam-binding inhibitor (DBI) have been purified from chicken intestine and identified as the intact avian polypeptide (residues 1-86) and a truncated variant (residues 35-86). At 10 nM concentration, both the intact and the truncated peptide suppress in vitro-monitored glucose-induced insulin release by 50 (p < 0.02) and 64% (p < 0.01) respectively. The truncation starts at a segment. -Thr-Val-Gly-Asp-, that is strictly conserved between characterized DBI species, indicating special restrictions on the structure. However, overall DBI conservation appears to be complex. A number of differently bioactive fragments with separate processings and tissue distributions have been observed, suggesting multiple functions of DBI and its sub-segments.
Chen
Z W
ZW
Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
Bergman
T
T
Jörnvall
H
H
Bonetto
V
V
Norberg
A
A
Mutt
V
V
Longone
P
P
Costa
E
E
Efendic
S
S
Ostenson
C G
CG
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D017124:Conserved Sequence; D026261:Diazepam Binding Inhibitor; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D007329:Insulin Antagonists / Q000494:pharmacology; D007422:Intestines / Q000737:chemistry*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017386:Sequence Homology, Amino Acid
D000596:Amino Acids; D002352:Carrier Proteins; D026261:Diazepam Binding Inhibitor; D007328:Insulin; D007329:Insulin Antagonists; D010446:Peptide Fragments; D005947:Glucose