Pyruvate Kinase: Difference between revisions

Line 26:

As can be seen, pyruvate kinase's <scene name='Keegan_Gelvoria_Sandbox_1/Secondary_structure/1'>secondary structure</scene> comprises of <scene name='Keegan_Gelvoria_Sandbox_1/Structure_4_domains/1'>four domains</scene> in humans. Thus, this enzyme is tetrameric with <scene name='Keegan_Gelvoria_Sandbox_1/Metal_binding_sites/1'>metal binding sites</scene> on each domain for the K+ and Mg2+ ligands to bind to. There are four types of tissue-specific isozymes: L (liver), R (red blood cells), M1 (muscle, heart, and brain), and M2 (early fetal tissue)<ref>{{website| title=SCOP: Protein: Pyruvate kinase (PK) from Human (Homo sapiens) [TaxId: 9606]|url=http://scop.berkeley.edu/data/scop.b.c.jh.b.b.d.html|}}</ref>.

==Kinetics and Regulation==

In the glycolytic cycle, there are three compounds that have a large negative ∆G which includes the reaction pyruvate kinase catalyzes. Due to these three steps regulating the overall activity of the cycle, they are generally irreversible in vivo. Through numerous researches, the activity of pyruvate kinase has been found to be regulated by these effectors:

a. Phosphoenolpyruvate, the substrate, can impact enzymatic activity by enhancing the reaction by allowing the process to operate faster with more substrate present.

b. ATP and pyruvate has been found to be a negative allosteric inhibitor.

c. Alanine has also been found to be a negative allosteric modulator.

As indicated earlier, phosphoenolpyruvate can enhance the activity of the reaction by adding into the enzyme because it is the rate limiting step. The enzyme follows hyperbolic kinetics. Experiments found that no incorporation was found in the reaction, indicating a random, rapid dissociation of the products. This, then, assumes that the products inhibit the enzyme’s reaction by simply reversing the reaction. Both pyruvate and ATP have been shown to be non-competitive inhibitors of pyruvate kinase.

==References==

Pyruvate Kinase: Difference between revisions

Navigation menu

Page actions

Page actions

Personal tools

Navigation

Search

Tools

@@ Line 26: / Line 26: @@
 As can be seen, pyruvate kinase's <scene name='Keegan_Gelvoria_Sandbox_1/Secondary_structure/1'>secondary structure</scene> comprises of <scene name='Keegan_Gelvoria_Sandbox_1/Structure_4_domains/1'>four domains</scene> in humans. Thus, this enzyme is tetrameric with <scene name='Keegan_Gelvoria_Sandbox_1/Metal_binding_sites/1'>metal binding sites</scene> on each domain for the K+ and Mg2+ ligands to bind to. There are four types of tissue-specific isozymes: L (liver), R (red blood cells), M1 (muscle, heart, and brain), and M2 (early fetal tissue)<ref>{{website| title=SCOP: Protein: Pyruvate kinase (PK) from Human (Homo sapiens) [TaxId: 9606]|url=http://scop.berkeley.edu/data/scop.b.c.jh.b.b.d.html|}}</ref>.
+==Kinetics and Regulation==
+In the glycolytic cycle, there are three compounds that have a large negative ∆G which includes the reaction pyruvate kinase catalyzes. Due to these three steps regulating the overall activity of the cycle, they are generally irreversible in vivo. Through numerous researches, the activity of pyruvate kinase has been found to be regulated by these effectors:
+a.	Phosphoenolpyruvate, the substrate, can impact enzymatic activity by enhancing the reaction by allowing the process to operate faster with more substrate present.
+b.	ATP and pyruvate has been found to be a negative allosteric inhibitor.
+c.	Alanine has also been found to be a negative allosteric modulator.
+As indicated earlier, phosphoenolpyruvate can enhance the activity of the reaction by adding into the enzyme because it is the rate limiting step. The enzyme follows hyperbolic kinetics. Experiments found that no incorporation was found in the reaction, indicating a random, rapid dissociation of the products. This, then, assumes that the products inhibit the enzyme’s reaction by simply reversing the reaction. Both pyruvate and ATP have been shown to be non-competitive inhibitors of pyruvate kinase.
 ==References==
 <references/>