Mapping and Identification of the Biomarker Peptide Derived from the Native VGF Protein

<div><p>The 3,959-Da “schizophrenia” peptide was mapped to amino acids 23–62 of the native VGF protein (in bold; underlined), immediately next to a predicted secretory signal peptide (using InterProScan: <a href="http://www.ebi.ac.uk/cgi-bin/iprscan" target="_blank">http://www.ebi.ac.uk/cgi-bin/iprscan</a>).</p> <p>Another native VGF-derived peptide did not show differential expression between healthy volunteers and patients with schizophrenia (as shown in <a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0030428#pmed-0030428-g002" target="_blank">Figure 2</a>A). This peptide has an identical sequence except that it is three amino acids shorter at the N-terminus compared to the “disease-specific” VGF peptide.</p>