Activated phosphorylation-dephosphorylation biochemical reaction cycles are a class of enzymatic futile cycles. A futile cycle such as a single MAPK cascade governed by two underlying enzymatic reactions permits Hyperbolic (H). Signal transducing (ST). Threshold-hyperbolic (TH) and Ultrasensitive (U) operating regimes that characterize input-output behaviour. https://macorners.shop/product-category/tote-bag/