TY - JOUR
T1 - Identification of a precursor form of cathepsin D in microsomal lumen
T2 - Characterization of enzymatic activation and proteolytic processing in vitro
AU - Nishimura, Yukio
AU - Higaki, Masahide
AU - Kato, Keitaro
N1 - Funding Information:
This work was supported in part by a Grant-Research from the Ministry of Education, Japan and a Grant from the Uehara Memorial
PY - 1987/10/14
Y1 - 1987/10/14
N2 - A precursor form of cathepsin D with 45 kDa was demonstrated in the rat liver microsomal lumen by immunoblotting analysis. The microsomal fraction containing procathepsin D which passed through a pepstatin-Sepharose resin showed no appreciable activity of cathepsin D. The in vitro incubation of this fraction at pH 3.0 resulted in a gradual increase of proteolytic activity toward hemoglobin as substrate and also, the proteolytic conversion of procathepsin D to the mature form was concomitantly observed. The proteolytic processing step was sensitive to pepstatin. These results suggest that procathepsin D is inactive in the endoplasmic reticulum and may be converted to the active forms by autoproteolytic processing mechanism at acidic pH during biosynthesis.
AB - A precursor form of cathepsin D with 45 kDa was demonstrated in the rat liver microsomal lumen by immunoblotting analysis. The microsomal fraction containing procathepsin D which passed through a pepstatin-Sepharose resin showed no appreciable activity of cathepsin D. The in vitro incubation of this fraction at pH 3.0 resulted in a gradual increase of proteolytic activity toward hemoglobin as substrate and also, the proteolytic conversion of procathepsin D to the mature form was concomitantly observed. The proteolytic processing step was sensitive to pepstatin. These results suggest that procathepsin D is inactive in the endoplasmic reticulum and may be converted to the active forms by autoproteolytic processing mechanism at acidic pH during biosynthesis.
UR - http://www.scopus.com/inward/record.url?scp=0023653476&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0023653476&partnerID=8YFLogxK
U2 - 10.1016/0006-291X(87)91115-6
DO - 10.1016/0006-291X(87)91115-6
M3 - Article
C2 - 3675582
AN - SCOPUS:0023653476
SN - 0006-291X
VL - 148
SP - 335
EP - 343
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 1
ER -