Journal: Scientific Reports

Article Title: Spiders’ digestive system as a source of trypsin inhibitors: functional activity of a member of atracotoxin structural family

doi: 10.1038/s41598-023-29576-y

Figure Lengend Snippet: Purification of Nephilingis cruentata MMD inhibitors. ( A ) Bovine trypsin inhibitory assay with the eluted fractions from the ionic-exchange batch separation and respective controls. (C1): control assay of bovine trypsin with 25 mM of ammonium bicarbonate at pH 8.5; (C2): control assay of bovine trypsin 25 mM of ammonium bicarbonate containing 1 M NaCl at pH 8.5; (C3): control assay of bovine trypsin with 25 mM of ammonium bicarbonate at pH 3.5; (1): Fraction eluted with 25 mM of ammonium bicarbonate at pH 8.5; (2): Fraction eluted with 25 mM of ammonium bicarbonate with 1 M NaCl at pH 8.5; (3): Fraction eluted with 25 mM of ammonium bicarbonate at pH 3.5. Inhibitory activity was measured using bovine trypsin 12 ng/µl as enzyme source and (0.1 mM) ZFRMCA as substrate (N = 3). ( B ) Chromatographic separation profile (UV at 214 nm) of fraction 2 (inhibitory active fraction against bovine trypsin), using a C18 column. Elution was performed by a linear gradient of 5% to 90% of solution B in 35 min. ( C ) SDS-PAGE in a 4–20% polyacrylamide gel of chromatographic peaks (P1-P6). Lane S molecular mass marker (97–14 kDa); lanes respectively: 1: P1; 2: P2; 3: P3; 4: P4; 5: P5; and 6: P6. The red arrow shows a single band detected by Coomassie blue G-250R. The approximate mass for the band on line 4 is 28.78 kDa calculated by gel relative migration.

Article Snippet: The samples eluted from chromatography on RP-HPLC (10 μg of protein) were loaded on 4–20% gradient SDS- PAGE gel kit Biocompare ( www.biocompare.com ) in reducing conditions.

Techniques: Purification, Control, Activity Assay, SDS Page, Marker, Migration