The RNA extraction and RT were done as described in Section 2.6. The PCR reaction was performed using the Taq HiFi DNA polymerase (Invitrogen) using temperature cycling as described in Section 2.6.1. After PCR amplification the products were purified from the agarose gel using a DNA extraction kit (Fermentas) as instructed by the manufacturer. Purified PCR products from rat mesentery were inserted into a plasmid vector

according to the manufacturer’s instructions (TOPO TA Cloning® Version K2, Invitrogen). Plasmids were transfected into Escherichia Apoptosis inhibitor coli and the positive clones were identified after DNA digestion with specific restriction enzymes, Bam HI and XhoI for CPA1 and Sal I and Not I for CPA2. The digestion products were analyzed by agarose gel as

described in Section 2.6.1 and the plasmids of the selected clones were purified (Promega, Madison, USA). Sequencing of 500 ng of DNA was done Y27632 in both directions by the BigDye terminator chemistry with an ABI 3100 Genetic Analyzer (Applied Biosystems, Foster City, CA) using M13 Forward and M13 Reverse primers. Sequence similarities between each individual rat mesenteric CPA and other known proteins were searched using the BLAST program (http://www.ncbi.nlm.nih.gov/blast/). The bands of interest of SDS-PAGE gels were excised and the proteins therein were reduced, alkylated and digested in-gel with trypsin. LC–MS/MS experiments to identify the peptides of individual digestion mixtures were performed at the Tufts University Core Facility on a Thermo LTQ ion trap mass spectrometer after separation of peptides on C18 column and microelectrospray ionization. The instrument was set at needle voltage of 3 kV, resolution of 3 Da, collision energy of 30% and recurring ions were excluded. LC–MS/MS data were searched against the NCBI non-redundant protein database (ftp://ftp.ncbi.nih.gov/blast/db/FASTA/nr)

using the SEQUEST algorithm oxyclozanide for protein identification. We have previously shown that rat MAB perfusate contains five Ang-processing CPAs that are distinguishable by their chromatographic behavior, substrate specificity and sensitivity to inhibitors [25]. Two of these enzymes were chosen to be further characterized in the present work as major representatives of Ang I and Ang II-processing activities of the rat MAB perfusate. As shown in Fig. 1A, an Ang-(1-7)-forming CPA was isolated by MonoQ anion-exchange chromatography from freshly prepared material analogous to that described as P4 in previous work [25]. This chromatographic step resulted in the purification of an enzyme to apparent homogeneity as judged by its migration during SDS-PAGE as a single component of molecular mass ca. 34 kDa (Fig. 1B).