Prolylendopeptidase Inhibitory Activity of a Glial Fibrillary Acidic Protein Fragment and Other Proline-rich Peptides

Abstract

The brain prolylendopeptidase (PEP) inhibitory activity of syn-thetic peptides related to the bovine brain-derived PEP inhibitor, GFAP-(38-55) (MPPPLPARVDFSLAGALN), was investigated. Homologous peptides such as MPPPLPTRVDFSLAGALN (human type) and MTPPLPARVDFSLAGALN (mouse type) also inhibited PEP. Among various synthetic fragments of GFAP-(38-55), only MPPPLP had a K_i essentially the same as that of GFAP-(38-55). Similar synthetic proline-rich peptides such as synapsin fragments and SH3 domain-binding peptides had more or less inhibitory activity.