title: Impulsive Enzymes: A New Force in Mechanobiology.
abstract: We review studies that quantify newly discovered forces from single enzymatic reactions. These forces arise from the conversion of chemical energy to kinetic energy, which can be harnessed to direct diffusion of the enzyme up a concentration gradient of substrate, a novel phenomenon of molecular chemotaxis. When immobilized, enzymes can move fluid around them and perform directional pumping in microfluidic chambers. Because of the extensive array of enzymes in biological cells, we also develop three new hypotheses: that enzymatic self diffusion can assist in organizing signaling pathways in cells, can assist in pumping of fluid in cells, and can impose biologically significant forces on organelles, which will be manifested as stochastic motion not explained by thermal forces or myosin II. Such mechanochemical phenomena open up new directions in research in mechanobiology in which all enzymes, in addition to their primary function as catalysts for reactions, may have secondary functions as initiators of mechanosensitive transduction pathways.
authors.affiliation: Department of Biomedical Engineering, The Pennsylvania State University, 205 Hallowell Building, University Park, PA 16802, USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Butler
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, PA 16802, USA.
authors.forename: Krishna K
authors.initials: KK
authors.lastname: Dey
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, PA 16802, USA.
authors.forename: Ayusman
authors.initials: A
authors.lastname: Sen
keywords: Cell mechanics; Chemotaxis; Cytoplasm; Diffusiophoresis; Mechanobiology; Molecular swimmer; Myosin; Phosphorylation; Rheology