Name: how cells control product buildup
Uploaded: 2019-03-11T09:21:10.000Z
Duration: 46 s
Channel: JoVE

- [Instructeur] in een regelgevingsproces genaamd feedback-remming, remt het product van een reactie een enzym in een eerdere stap in de metabolische baan die het produceerde, waardoor het zijn eigen productie vertraagt of afsluit. Het product doet dit door zich te binden aan een regulerende plaats op het enzym, die verschilt van de actieve plaats die aan het substraat bindt. Wanneer het product zich bindt aan de regulerende plaats, veroorzaakt het een conformationele verandering in het enzym waardoor de voortzetting om de reactie te katalyseren wordt afgeremd.

Deze activiteit voorkomt dat zich te hoge niveaus van het product ophopen. En zodra het niveau laag genoeg daalt, remt het product het enzym niet meer en kan de productie gewoon doorgaan.

feedback-remming

Feedback Inhibition

Biochemische reacties vinden voortdurend plaats in cellen, waarbij uitgangsstoffen worden omgezet in verschillende producten, meestal met behulp van enzymen die de reacties versnellen. Zonder enzymen zouden de meeste reacties te traag verlopen om nuttig te zijn voor de cel.

Omdat enzymen de reactiesnelheid reguleren, wordt hun activiteit gecontroleerd om ervoor te zorgen dat de juiste hoeveelheden uitgangsmaterialen, tussenproducten en eindproducten in de cel worden gehandhaafd. Een overmatige ophoping of uitputting van stoffen kan ernstige gevolgen hebben voor de gezondheid van de cel en het organisme.

In een regulerend proces dat feedbackinhibitie wordt genoemd, remt het product van een reactie een enzym dat betrokken is bij een eerdere stap van de metabolische route die het heeft geproduceerd. Het product bindt zich aan een regulerende plaats op het enzym, die verschilt van de actieve plaats waar het substraat zich normaal bindt. Dit leidt tot een vertraging of stopzetting van de productie van het product. Wanneer het product zich aan de regulerende plaats bindt, veroorzaakt het een conformationele verandering in het enzym, waardoor het niet langer aan het substraat kan binden en de reactie niet meer kan worden gekatalyseerd.

Dit voorkomt een te hoge ophoping van het product in de cel. Zodra het productniveau laag genoeg is, remt het niet langer het enzym, en de reactie kan opnieuw verlopen zoals gewoonlijk.

Feedback-remming

Biochemical reactions are occurring constantly in cells, converting starting substances to different products, usually with the help of enzymes that speed ...

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how cells control product buildup

Cells use enzymes to run biochemical reactions and make the products they need. These reactions are happening constantly, and enzymes speed them up so they happen fast enough to matter. Enzyme activity also has to be regulated. Cells need the right amounts of starting materials, intermediate metabolites, and final products.

If these substances build up too much or drop too low, the cell can be harmed. That is why cells use control systems to keep metabolic levels balanced. One important control process is feedback inhibition. In this process, the final product of a reaction slows an enzyme from an earlier step in the same pathway.

The product binds to a regulatory site on the enzyme. This site is different from the active site, which is where the substrate normally binds. Binding at the regulatory site changes the enzyme’s shape. That conformational change prevents the enzyme from binding the substrate and keeps the reaction from continuing.

Feedback inhibition helps stop too much product from accumulating in the cell. When product levels fall, the product no longer inhibits the enzyme. The pathway can then start again and continue producing the molecule as needed.

How Cells Control Product Buildup

what is metabolism?

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Metabolism is the set of chemical reactions that happen in a cell. It includes anabolism, which builds molecules, and catabolism, which breaks them down. These reactions help cells manage energy and keep life processes running. Cells use metabolism to turn food into energy, make cell parts, and remove waste products. Food stores potential energy in the bonds between atoms. Catabolic pathways break large food molecules into smaller ones and release that energy. Anabolic pathways use that energy...

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feedback inhibition

Cells use enzymes to run biochemical reactions and make the products they need. These reactions are happening constantly, and enzymes speed them up so they happen fast enough to matter. Enzyme activity also has to be regulated. Cells need the right amounts of starting materials, intermediate metabolites, and final products. If these substances build up too much or drop too low, the cell can be harmed. That is why cells use control systems to keep metabolic levels balanced. One important...

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key terms and concepts

Learn how feedback inhibition lets cells regulate enzymes, stop product buildup, and keep metabolic reactions balanced in high school biology.

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How Cells Control Product Buildup

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