Pepsinogen, the inactive precursor of pepsin which belongs to the group of aspartic proteinases, is synthesized in the
chief cells of gastric glands. Seven electrophoretically separable pepsinogens exist in human gastric mucosa. One group
(Pg1-Pg5), called PGA or group I pepsinogen , is characterized by electrophoretically faster migration and
localization in the fundus and body of the stomach; the second group (Pg6 and Pg7), termed pepsinogen C, is localized
in the whole stomach.
General function
Hydrolase, Peptidase/Protease
Comment
Cellular localization
Secreted
Comment
Ovarian function
Ovulation
Comment
Bobe J, et al 2001 reported that an ovarian progastricsin is present in the trout coelomic fluid
after ovulation.
An up-regulated cDNA fragment was isolated using a differential display
polymerase chain reaction between ovulatory and postovulatory brook trout
ovarian tissues. Using this fragment as a probe, a full-length cDNA of 1783
base pairs was obtained from an ovarian cDNA library. The cDNA presumably
codes for a 383-amino acid protein with strong sequence similarity to an
aspartic protease, progastricsin (EC 3.4.23.3), also known as pepsinogen C. On
Northern blots of ovarian tissue, the trout progastricsin cDNA hybridized with
a 1.8-kilobase transcript that was strongly up-regulated 4-6 days after
ovulation. Of all other tissues tested, a transcript was only detected in the stomach. On Western blots of ovarian tissue, the progastricsin
antibody recognized a single 39-kDa protein that was present in the ovary only
following ovulation. On Western blots of coelomic fluid, the 39-kDa protein
was strongly detected 4-10 days after ovulation. The trout progastricsin was
immunocytochemically localized to the granulosa cells of postovulatory
follicles, suggesting that it is released from this tissue into the coelomic
fluid following ovulation.