Lb. Nielsen et Hh. Nielsen, Purification and characterization of cathepsin D from herring muscle (Clupea harengus), COMP BIOC B, 128(2), 2001, pp. 351-363
Citations number
55
Categorie Soggetti
Biochemistry & Biophysics
Journal title
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY
Cathepsin D was purified and concentrated 469-fold from a homogenate of Clu
pea harengus muscle. The purified enzyme is a monomer with a molecular weig
ht of 38 000-39 000. It is inhibited by pepstatin and has optimal activity
at pH 2.5 with hemoglobin as the substrate. The isoelectric point is at pH
6.8. Glycosidase treatment and binding to Concanavalin A indicated that the
enzyme contains one N-linked carbohydrate moiety of the high-mannose type
per molecule. The first 21 amino acid residues of the N-terminal showed hig
h similarity to cathepsin D from antarctic icefish liver (Chionodraco hamat
us) and trout ovary (Oncorhynchus mykiss). Digestion of the P-chain of oxid
ized insulin resulted in preferential cleavage at Leu(15)-Tyr(16), (47%), T
yr(16)-Leu(17) (34%) and Ala(14)-Leu(15) (18%). Incubation with myofibrils
from herring muscle at pH 4.23 showed that the enzyme mainly degraded myosi
n, actin and tropomyosin. (C) 2001 Elsevier Science Inc. All rights reserve
d.