35° is supposed to be the ideal degree for the enzyme (because the body temperature is 37°), so why did the 35° temperature affect the enzyme by changing its shape?? (despite the dismantling of the starch)
They never say that its shape changes at 35 C. The timing of the animation does make it seem like that's what they're saying though, I'll give you that. But the animation is just an example of amylase changing shape at a higher temp, not at 35 C, to help illustrate why it stops functioning. Its optimal range is about 50 C, so not at 35 C (I have a theory why that I'll leave below all this). Amylase continues to be effective, though decreasingly so, up to around 70 C, at which point the efficiency drops off more severely as its deformation becomes more and more pronounced. It's even effective well below 35 C, down to about 10 C by most studies. As we see in this video there is still detectable activity even at 5 C. It's quite a hardy little enzyme it turns out. Why not optimal at 37 C/human temp??? Strap in. It's a long comment on the Internet. "Amylase" is a class of enzymes, defined by which molecules they "attack" and the manner in which they do what they do or _how_ they "attack" those molecules. Here, "salivary" amylase refers to alpha-amylase. There are beta- and gamma-amylases as well. They all use the same mechanism to turn starches into sugars, only the slight differences in form between each cause them to perform their task elsewhere on the starch molecule or more optimally in different pH or temperature environments. Why such a wide range? Well, humans aren't the only organisms to take advantage of amylases. This can help explain why alpha-amylase's optimal range is well above our body temp -- these protein structures need to maintain function across a wide array of environments. Plants, humans, vegetables, sea critters, and many others all have the genetic blueprint to make one or more of these enzymes we call amylases. These enzymes are crucial to the organisms' survival as they help to ensure energy availability. It's also kind of a nod to evolution by natural selection when you think about it. Each species _could_ have a set of perfectly tuned enzymes that function at 100% efficiency within that organism's system (each organism's specific pH and temp). Or, somewhere along the line, in a completely different environment than we have today, some organism happened to code for a useful enzyme that helped it survive. Unbeknownst to that organism, its fancy new enzyme had a pretty high tolerance for changes in its environment. So, over time, we all inherited this incredibly useful enzyme's blueprint because it continued to prove useful to subsequent generations. Generations that had it, survived, while those that lacked it died off if they couldn't find another way to efficiently extract energy. Thus, the blueprint for this enzyme class, amylases, gets passed down and is widely distributed (that's why we share this enzyme with sweet potatoes). Now, today, even though our human system is not perfectly optimal for it, the enzyme still functions sufficiently well to increase our chance of survival. It's not survival of the fittest, but the survival of the good enough. So, if you're some ancient organism, fine-tuning enzymes on a species-by-species basis for yourself would make you one of the "fittest species," but attempting to do so when the world is trying to kill you is kind of a waste of time, time that could be spent proliferating the species before the world kills you. Long comment. But I kind of just went with it. I hope you don't mind. I think enzymes and hormones are cool. Sue me.
It will still convert starch to maltose. At around 70 C "salivary" (alpha) amylase will begin to deform such that it becomes inactive. Its optimal temp is about 50 C.
If I'm not mistaken, I think that means all the starch molecules present earlier is broken down to amylase by the enzyme(amylase) since function of iodine solution used is to identify the presence of starch...if there's no change in colour there is no starch left
why not just add the iodine solution into the testtubes? They will all be dark blue to begin with. The moment all starch in a testtube is gone, the colour will change to red/brown
