Difference between kinase and phosphorylase

Main difference

The main difference between kinase and phosphorylase is that kinase catalyzes the addition of phosphate from ATP to the acceptor, while phosphorylase from inorganic phosphate (Pi).

Kinase vs. phosphorylase

Kinase was first observed in the liver as a protein kinase by Gene Kennedy in 1954, while phosphorylase was observed by Earl W. Sutherland Jr. in the late 1930s as glycogen phosphorylase.

When the donor agency is the high-energy ATP molecule, the enzyme involved is a kinase, and when the donor agency is inorganic phosphate such as PO 3- H 3 PO 4 (phosphoric acid) as a source of phosphorylation, the enzyme involved is phosphorylase. . Kinase acceptors are organic molecules like carbohydrates, lipids and proteins, etc., while phosphorylase acceptors are specific substances or monomeric subunits like glycogen, starch, etc.

Kinases are not involved in breaking the bonds of a substrate during the transfer of the phosphate group, whereas phosphorylase breaks the bonds of the substrate and the specific substance by adding the phosphate group. The typical type of kinase is protein kinase among carbohydrate and lipid kinases, while the common type of phosphorylase is glycogen phosphorylase.

Comparative chart

Kinase Phosphorylase
Phosphorylation takes place by the addition of high-energy ATP phosphate, known as kinase. Phosphorylation occurs by the transfer of phosphate from inorganic phosphate, which is known as phosphorylase.
In 1954 In the late 1930s
Phosphate source
ATP (organic chemical) Inorganic phosphate (Pi)
Bond breakage
Do not break the substrate bonds Break the substrate bonds
Organic molecules (glucose, proteins, lipids, etc.) Monomeric molecules such as glucose, lactose
PH range
About 7.4, also 5.0 From 6-7
Protein kinases, lipid kinases, carbohydrate kinases, etc. Glycogen phosphorylases, etc.
What is kinase?

Biological catalyst kinase is one of the types of phosphotransferases that catalyze phosphorylation by transferring the phosphate group from inorganic phosphate (PO 3- ). The kinase acts in various enzymatic reactions, not involved in the breaking of substrate bonds.

Kinases play the role of phosphotransferase, which regulates cell functions by transferring phosphate from donor ATP to substrate molecules such as glucose, proteins, and lipids. The kinase does not break the bonds of the substrate molecules on which it acts during the transfer of phosphate groups. Some of the substrates are riboflavin, creatine, etc. The kinase acts as a source of transmission of signals that regulate complex processes in cells.

Kinase classification

  • Protein kinase: One of the most diverse and important functional families of kinases is a protein kinase. They take care of the functions and activity of many proteins by adding phosphates to amino acids such as tyrosine, threonine, serine, and also histidine. P13K combines phosphorus with oxygen.
  • Lipid kinase: they act on the reactivity of the substrate lipids by adding phosphate as phosphoinositide three kinases involved in causing cancer when this lipid kinase acts on the catalytic subunit PIK3CA (provides instructions to produce the p110 alpha protein).
  • Carbohydrate Kinase: These kinases act on the substrate of carbohydrates such as glucose and hexokinase (an enzyme used during glycolysis) regulating various metabolic pathways.

What is phosphorylase?

Phosphorylase is also one of the types of phosphotransferases that catalyze the phosphorylation of inorganic phosphates (Pi) to acceptor molecules. Phosphorylase enzymes are involved in breaking the bonds of the substrate and the monomer molecule, unlike phosphate kinase (PO 3- ). It is regulated by phosphorylation and also by allosteric regulation (binding of the enzyme to a site other than the enzyme’s active site on the effector molecule).

Phosphorylase is the active form in the sense of activation of the enzymes that phosphorylase b. In the process of phosphorylation, the process requires ATP, whereas dephosphorylation, free inorganic phosphate released as P i . Phosphorylases are different from phosphatases that remove the phosphate group from the donor through water. Phosphorylases also include allosteric enzymes (they can change their shape by binding to the effector, which play the role of catalyst for the production of glucose-1-phosphate from glucan, such as glycogen, starch, etc.

Accordingly, they are named by adding a substrate name with the phosphorylase as glycogen / starch phosphorylase is named when the starch substrate acts by phosphorylase during the phosphate addition of an inorganic phosphate.

Examples of phosphorylase are trehalose phosphorylase, glycogen / starch phosphorylase (in glycogenesis), polynucleotide phosphorylase. Enzyme disorders caused by phosphorylase are type V glycogen storage disease – muscle glycogen and type VI glycogen storage disease – liver glycogen.

Classification of phosphorylase

  • Glucosyl phosphotransferase: enzymes that remove glucose from glucans, eg, maltodextrin phosphorylase, starch phosphorylase. Enzymes break nucleosides into subunits of bases and sugars, eg, purine nucleosides phosphorylase.
  • Nucleotidyl phosphotransferase: having exonuclease activity at the 3 ‘to 5’ position, eg, phosphorylated polynucleotide.

Key differences

  1. Kinases add phosphate from ATP to the substrate, while phosphorylase adds phosphate from inorganic phosphate to the substrate.
  2. Kinases do not involve bond breaking, whereas phosphorylase involves bond breaking in substrate molecules.
  3. Kinase adds phosphate to organic molecules like carbohydrates, proteins, and lipids; Phosphorylase adds phosphate to monomers like glycogen, starch, etc.
  4. Kinases are only regulated by phosphorylation; on the other hand, phosphorylases are regulated by both allosteric and phosphorylation.
  5. Kinase involves proteins, lipid kinases, while phosphorylase involves glycogen, starch phosphorylase.
  6. The kinase uses ATP; Phosphorylase uses inorganic phosphate as a source of phosphate in a substrate.
  7. Kinases include lipid kinases, protein kinases, and carbohydrate kinases; conversely, phosphorylases include starch phosphorylase, glycogen phosphorylase, and polynucleotide phosphorylase.
Final Thought

Kinase is a type of phosphotransferase that dominates ATP phosphate, while phosphorylase donates inorganic phosphate phosphate to the substrate molecule.

Leave a Reply

Your email address will not be published. Required fields are marked *


Back to top button