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Endoproteolysis of non‐CAAX‐containing isoprenylated peptides
Author(s) -
Ma Yu-Ting,
Rando Robert R.
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80493-e
Subject(s) - chemistry
A microsomal endoprotease specifically cleaves isoprenylated peptides of the CAAX motif, such as N ‐acetyl‐ S ‐all‐ trans ‐farnesyl‐ l ‐cysteine (AFC‐VIM), at the isoprenylated cysteine residue. It is shown here that endoproteolysis will also occur with peptides which are not of the CAAX type. Peptide substrates modeled after the Delta virus large antigen carboxyl‐terminus (CRPQ) are endoproteolytically hydrolyzed by liver microsomes. AFC‐RPQ is hydrolyzed with a K M = 12.4 μM and a V max = 0.27 nmolmin/mg, and AGGC‐RPQ is hydrolyzed with a K M = 7.9 μM and a V max = 0.042 nmolmin/mg. Moreover, a series of potent inhibitors of the endoproteolysis of AFC‐AAX‐containing peptides are ineffective at inhibiting the hydrolysis of AFC‐RPQ and AGGC‐RPQ, suggesting the existence of isoforms of the endoprotease.