Purification and characterization of rat pepsinogens whose contents increase with developmental progress

Area of Science:

• Biochemistry
• Enzymology
• Gastroenterology

Background:

• Pepsinogens are precursors to pepsins, crucial digestive enzymes.
• Understanding pepsinogen heterogeneity is vital for gastric physiology research.

Purpose of the Study:

• To purify and characterize pepsinogens from adult rat gastric mucosa.
• To compare the biochemical and catalytic properties of purified pepsinogens I and II.

Main Methods:

• Purification using ammonium sulfate fractionation and ion-exchange chromatography (DEAE-cellulose, DEAE-Sepharose CL-6B).
• Homogeneity assessment via polyacrylamide gel disc electrophoresis.
• Molecular weight determination using SDS-polyacrylamide gel electrophoresis.
• Enzyme activity assays and stability studies at various pH levels.

Main Results:

• Two homogeneous pepsinogens, I and II, were isolated and designated.
• Pepsinogen II exhibited higher anodic electrophoretic mobility than pepsinogen I at pH 8.0.
• Both pepsinogens yielded activated pepsins with a molecular weight of 32,000.
• Pepsin I and II showed optimal activity at pH 2.0 and stability at pH 8.0.
• Enzymes were inhibited by pepstatin and DAN, with substrate hydrolysis activity 1/8 that of porcine pepsin.

Conclusions:

• Pepsinogens I and II are distinct but share highly similar biochemical and catalytic characteristics.
• The findings suggest functional redundancy or specialized roles for these pepsin variants in rat digestion.