A crude extract of porcine anterior pituitary was found to contain endopeptidase activity that splits the Leu77-Phe78 peptide bond of β-lipotropin in a pH range 3.0-7.0. The specificity and susceptibility to pepstatin of pituitary extract were the same as those of cathepsin D (E.C. 220.127.116.11) isolated from calf brain by affinity chromatography. Cathepsin D was shown to split the same Leu-Phe peptide bond of β-endorphin, leading to the formation of γ-endorphin. Based on the above data it is suggested that cathepsin D is a major factor in the generation of endorphins of intermediate size.
ASJC Scopus subject areas
- Molecular Biology