Protein denaturation and edible toxins
Why people still die after eat them even boiled to 100 oC, but why?


Well not all toxins are protein based. Some are just small molecules that fit into some vital protein in your body, causing  it to stop and death not long later. Some are cyclic peptides and are not denatured by heat. The peptide is simple, and has many carbon bonds to stablize its structure (it is a ring and has carbon bonds linking internally) https://en.wikipedia.org/wiki/%CE%91-amanitin


  Or is there any absolute temperature and time to kill most type of protein ?


Autoclaving.. 134 °C (274 °F) for 18 minutes in a pressurized steam can destroy prions. And prions pretty tough. https://en.wikipedia.org/wiki/Prion