Three modes of reversible inhibition
Competitive inhibitors resemble the substrate and bind the active site, so they raise the apparent Km while leaving Vmax unchanged, because enough substrate can outcompete them. Non-competitive inhibitors bind an allosteric site equally well whether or not substrate is bound; they lower Vmax and leave Km unchanged. Uncompetitive inhibitors bind only the enzyme-substrate complex, lowering both Vmax and Km.
These are reversible inhibition types. Irreversible inhibitors, by contrast, form covalent bonds and permanently inactivate the enzyme.
Reading the Lineweaver-Burk plot
The double-reciprocal Lineweaver-Burk plot makes the modes visually distinct. Competitive inhibition shifts the x-intercept but keeps the same y-intercept (shared Vmax). Non-competitive inhibition changes the y-intercept while the x-intercept stays fixed. Uncompetitive inhibition shifts both intercepts, producing lines parallel to the uninhibited line.