High Enrichment of MMP-9 and Carboxypeptidase A by Tweezing Adsorptive Bubble Separation (TABS) Dirk Haller & Perihan Ekici & Albrecht Friess & Harun Parlar Received: 29 October 2009 / Accepted: 17 February 2010 / Published online: 14 March 2010 # Springer Science+Business Media, LLC 2010 Abstract Tweezing adsorptive bubble separation (TABS) was used as a method for the enrichment of matrix metalloproteinases (92-kDa type IV, gelatinase B (MMP-9)) and carboxypeptidase A (CPA) from dilute aqueous solutions. The method is based on the chelation of metalloenzymes applying 2-(carbamoylmethyl-(carboxymethyl)amino)acetic acid (ADA) coupled with an octyl part to form a surface active unit. MMP-9 could be enriched with an enrichment ratio of 12.0 and a recovery of 87.3%, and CPA could be enriched 18.8-fold and with 95.3% recovery. Both enzymes were enriched without significant losses of enzymatic activity. To verify that the enzymes were tweezed by ADA-C8 without abstraction of the zinc ions from the active center, TABS trials were additionally conducted with zinc ions in complex with ADA-C8, which revealed only negligible enrichment ratios of the enzymes (2.2 for MMP- 9 and 0.2 for CPA). The results obtained impressively demonstrate that zinc-containing proteases can be enriched selectively and efficiently by TABS. Keywords Tweezing adsorptive bubble separation . MMP-9 . Carboxypeptidase A . Matrix metalloproteinases . Carboxypeptidases Introduction Carboxypeptidases and matrix metalloproteinases (MMPs) belong to the family of medically important metalloproteases with diverse positive and negative functions in the human body [1]. According to classification, the pancreatic carboxypeptidase A (CPA) is Appl Biochem Biotechnol (2010) 162:1547–1557 DOI 10.1007/s12010-010-8936-x D. Haller Chair for Biofunctionality, ZIEL-Research Center for Nutrition and Food Science, Technische Universität München, Gregor-Mendel-Str. 2, 85350 Freising-Weihenstephan, Germany P. Ekici : A. Friess : H. Parlar (*) Department for Chemical–Technical Analysis and Chemical Food Technology; Research Center Weihenstephan for Brewing and Food Quality, Technische Universität München, Weihenstephaner Steig 23, 85354 Freising-Weihenstephan, Germany e-mail: parlar@wzw.tum.de