Activity of Anchored Human Matrix Metalloproteinase-1 Catalytic Domain on Au (111) Surfaces Monitored by ESI-MS

Matrix metalloproteinases (MMPs) are a family of Zn-dependent endo-peptidases known for their abilityto cleave several components of the extracellular matrix, but which can also cleave many non-matrixproteins. There are many evidences that MMPs are involved in physiological and pathological processes,and a huge effort has been put in the development of possible inhibitors that could reduce the activity ofMMPs, as it is clear that the ability to monitor and control such activity plays a pivotal role in the search forpotential drugs aimed at finding a cure for several diseases such as pulmonary emphysema, rheumatoidarthritis, fibrotic disorders and cancer.A powerful method currently available to study enzyme–inhibitor interactions is based on the useof the surface plasmon resonance (SPR) technique. When MMP interactions are studied, a procedure bywhich inhibitors are normally anchored on sensor chips and SPR technique is used in order to study theirinteraction with MMPs molecules is usually followed. This is because it is currently believed that MMPscannot be anchored on the sensor-chip surface without losing their activity. However, this approach givesrise to problems, as the anchoring of low-molecular-weight inhibitors on gold surfaces easily affects theirability to interact with MMPs. For this reason, the anchoring of MMPs is highly desirable.A new experimental protocol that couples the Fourier transform-SPR (FT-SPR) technique withelectrospray ionization-mass spectroscopy (ESI-MS) is described here for the evaluation of the activityof MMP-1 catalytic domain (cdMMP-1) anchored on gold surfaces. The cdMMP-1 surface coverage iscalculated by using FT-SPR and the enzyme activity is estimated by ESI-MS. The proposed method islabel-free.