Characterization of four substrates emphasizes kinetic similarity between insect and human C-domain angiotensin-converting enzyme.
Angiotensin converting enzyme (ACE) was already discovered in insects in 1994, but its physiological role is still enigmatic. We have addressed this problem by purifying four new ACE substrates from the ovaries of the grey fleshfly, Neobellieria bullata. Their primary structures were identified as NKLKPSQWISLSD (Neb-ODAIF-1(1-13)), NKLKPSQWI (Neb-ODAIF-1(1-9)), SLKPSNWLTPSE (Neb-ODAIF-2) and LEQIYHL. Database analysis showed significant homology with amino acid sequence stretches as present in the N-terminal part of several fly yolk proteins. An antiserum raised against Neb-ODAIF-1(1-9) immunostained one out of three yolk protein bands of SDS/PAGE-separated fly haemolymph and egg homogenate, thus confirming that these peptides originate from a yolk protein gene product. Kinetic analysis of these peptides and of the peptides Neb-ODAIF and Neb-ODAIF-1(1-7) with insect ACE and human ACE show both similar and unique properties for insect ACE as compared with human C-domain ACE.
Zoological Institute of the Catholic University of Leuven, Laboratory of Developmental Physiology and Molecular Biology, Leuven, Belgium. korneel.hens@bio.kuleuven.ac.be
Korneel
K
Hens
Anick
A
Vandingenen
Nathalie
N
Macours
Geert
G
Baggerman
Adriana Carmona
AC
Karaoglanovic
Liliane
L
Schoofs
Arnold
A
De Loof
Roger
R
Huybrechts
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004175:Diptera / Q000201:enzymology; D004527:Egg Proteins / Q000302:isolation & purification / Q000378:metabolism*; D005260:Female; D006110:Grasshoppers / Q000201:enzymology; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008969:Molecular Sequence Data; D010053:Ovary / Q000201:enzymology; D010455:Peptides / Q000378:metabolism; D007703:Peptidyl-Dipeptidase A / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013379:Substrate Specificity; D013737:Testis / Q000201:enzymology
D004527:Egg Proteins; D019476:Insect Proteins; D010455:Peptides; D011993:Recombinant Fusion Proteins; D007703:Peptidyl-Dipeptidase A