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Updated: Aug 14, 2026
Non-invasive In Vivo Fluorescence Optical Imaging of Inflammatory MMP Activity Using an Activatable Fluorescent Imaging Agent
Published on: May 8, 2017
Design and characterization of a fluorogenic substrate selectively hydrolyzed by stromelysin 1 (matrix
H Nagase1, C G Fields, G B Fields
1Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66103.
Abstract:
Members of the matrix metalloproteinase (MMP) family have been implicated in disease states such as arthritis, periodontal disease, and tumor cell invasion and metastasis. Stromelysin 1 (MMP-3) has a broad substrate specificity and participates in the activation of several MMP zymogens. We examined known sequences of MMP-3 cleavage sites in natural peptides and proteins and compared sequence specificities of MMP-3 and interstitial collagenase (MMP-1) in order to design fluorogenic substrates that (i) would be hydrolyzed rapidly by MMP-3, (ii) would discriminate between MMP-3 and MMP-1, and (iii) could be monitored continuously without interference from MMP amino acid residues. Designed substrates were then screened for activity toward MMP-1, gelatinase A (MMP-2), MMP-3, and gelatinase B (MMP-9). The first of these substrates, NFF-1 (Mca-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Lys-(Dnp)-Gly, where Mca is (7-methoxycoumarin-4-yl)acetyl and Dnp is 2,4-dinitrophenyl), was hydrolyzed equally well by MMP-3 and MMP-2 (kcat/Km approximately 11,000 s-1 M-1). MMP-1 had 25% of the activity of MMP-3 toward NFF-1. The second substrate, NFF-2 (Mca-Arg-Pro-Lys-Pro-Tyr-Ala-Nva-Trp-Met-Lys(Dnp)-NH2, where Nva is norvaline), was hydrolyzed 60 times more rapidly by MMP-3 (kcat/Km = 59,400 s-1 M-1) than MMP-1. Unfortunately, NFF-2 showed little discrimination between MMP-3, MMP-2 (kcat/Km = 54,000 s-1 M-1), and MMP-9 (kcat/Km = 55,300 s-1 M-1). The third substrate, NFF-3 (Mca-Arg-Pro-Lys-Pro-Val-Glu-Nva-Trp-Arg-Lys(Dnp)-NH2), was hydrolyzed rapidly by MMP-3 (kcat/Km = 218,000 s-1 M-1) and very slowly by MMP-9 (kcat/Km = 10,100 s-1 M-1), but there was no significant hydrolysis by MMP-1 and MMP-2. NFF-3 is the first documented synthetic substrate hydrolyzed by only certain members of the MMP family and thus has important application for the discrimination of MMP-3 activity from that of other MMPs. Although NFF-3 was designed by assuming that substrate subsites were independent and hence free energy changes derived from single mutation experiments were additive, we found discrepancies between predicted and experimental kcat/Km values, one on the order of 2000-5000. Thus, the design of additional discriminatory MMP substrates may require approaches other than assuming additive free energy changes, such as screening synthetic libraries and consideration of secondary and tertiary structures of substrates and the enzyme.
Insights
Researchers developed novel fluorogenic substrates to specifically detect matrix metalloproteinase-3 (MMP-3) activity. NFF-3 effectively distinguishes MMP-3 from other MMPs, aiding disease research.
Area of Science:
- Biochemistry
- Enzymology
- Molecular Biology
Background:
- Matrix metalloproteinases (MMPs) are implicated in diseases like arthritis, periodontal disease, and cancer metastasis.
- Stromelysin 1 (MMP-3) has broad substrate specificity and activates other MMPs, making specific detection challenging.
- Existing methods lack substrates that can reliably differentiate MMP-3 activity from other MMPs.
Purpose of the Study:
- To design and synthesize novel fluorogenic substrates for matrix metalloproteinases (MMPs).
- To develop substrates with rapid hydrolysis by MMP-3 and selective discrimination against MMP-1.
- To enable continuous monitoring of MMP activity without interference from amino acid residues.
Main Methods:
- Analyzed known MMP-3 cleavage sites in natural substrates.
- Compared sequence specificities of MMP-3 and MMP-1.
- Designed and screened fluorogenic substrates (NFF-1, NFF-2, NFF-3) against MMP-1, MMP-2, MMP-3, and MMP-9.
Main Results:
- NFF-1 showed equal hydrolysis by MMP-3 and MMP-2, with MMP-1 activity at 25% of MMP-3.
- NFF-2 hydrolyzed rapidly by MMP-3 but lacked discrimination between MMP-3, MMP-2, and MMP-9.
- NFF-3 was rapidly hydrolyzed by MMP-3 and slowly by MMP-9, with no significant activity from MMP-1 or MMP-2, marking it as the first selective substrate.
Conclusions:
- NFF-3 is the first synthetic substrate that selectively detects MMP-3 activity, distinguishing it from other MMPs.
- The design of NFF-3 revealed discrepancies between predicted and experimental values, suggesting limitations in assuming additive free energy changes.
- Future discriminatory MMP substrate design may require advanced approaches like library screening and consideration of enzyme-substrate structural interactions.
