Expression, purification and characterization of a Kunitz-type protease inhibitor domain from human amyloid precursor protein homolog

• Published in: FEBS letters Vol. 338; no. 1; pp. 53 - 57
• Main Authors: Petersen, Lars C., Bjørn, Søren E., Norris, Fanny, Norris, Kjeld, Sprecher, Cindy, Foster, Donald C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 24.01.1994; Elsevier
• Subjects: Alzheimer; Amino Acid Sequence; Amyloid beta-Protein Precursor - genetics; Amyloid beta-Protein Precursor - metabolism; Amyloid precursor protein homolog; Analytical, structural and metabolic biochemistry; APP, amyloid precursor protein; APPH, amyloid precursor protein homolog; Base Sequence; Biological and medical sciences; BPTI, bovine pancreatic trypsin inhibitor; DNA, Complementary; Factor XIa; Fundamental and applied biological sciences. Psychology; Glycoproteins; Humans; KPI, Kunitz-type protease inhibitor; Kunitz-type protease inhibitor; Molecular Sequence Data; Proteins; Serine protease; Trypsin Inhibitors - genetics; Trypsin Inhibitors - isolation & purification; Trypsin Inhibitors - metabolism; Factor XIa; BPTI, bovine pancreatic trypsin inhibitor; Amyloid precursor protein homolog; APPH, amyloid precursor protein homolog; Serine protease; KPI, Kunitz-type protease inhibitor; Alzheimer; Kunitz-type protease inhibitor; APP, amyloid precursor protein; Human; Heterologous system; Kunitz inhibitor; Yeast; Nucleotide sequence; Enzyme; Enzyme inhibitor; Amyloid precursor protein; Domain structure; Hydrolases; Proteinases; Aminoacid sequence; Structural analysis
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(94)80115-0

The Kunitz-type protease inhibitor domain from a recently identified homolog of the Alzheimer amyloid precursor protein (APPH KPI) was expressed in yeast, purified and characterized. Its inhibition profile towards several serine proteases was studied and compared to that of APP KPI, the Kunitz domain from the Alzheimer amyloid precursor protein. APPH KPI was shown to inhibit proteases with trypsin-like specificity with an inhibitor profile resembling that of the APP KPI domain. The KPI domains from APP and APPH inhibited trypsin ( K i = 0.02 nM), and plasma kallikrein ( K i = 86 nM) with approximal equal affinity. In comparison to APP KPI ( K i = 82 nM) the KPI domain of the homolog, APPH KPI, ( K i = 8.8 nM) was a more potent inhibitor of glandular kallikrein. APPH KPI was a less potent inhibitor of chymotrypsin than APP KPI ( K i = 78 nM as compared to K i = 6 nM), plasmin ( K i = 81 nM as compared to 42 nM), and factor XI a ( K i = 14 nM as compared to K i = 0.7 nM). The affinity of factor XI a for APPH KPI is sufficiently high to allow for an interaction in the blood. It is, however, well possible that the physiological protease ligand for the receptor-like APPH protein has yet to be identified.