What are the differences between kinases and phosphorylases?

Question

Accepted Answer

Basis of differentiation

Kinases

Phosphorylases

Definition

Kinases refer to enzymes that catalyze the transfer of a phosphate group from ATP or GTP to its protein substrates

Phosphorylases refer to enzymes which catalyze phosphorylation through inorganic phosphates

Addition of phosphate groups

Kinases add phosphate groups to existing organic molecules (does not break the bonds in the substrate)

Addition of phosphate groups by phosphorylases break bonds in the substrate

Regulation

Regulated by phosphorylation

Regulated by phosphorylation or allosteric regulation

Co-substrate requirement

Uses a phosphate group from ATP or GTP  for phosphorylation reactions

Uses inorganic phosphate groups as the donor of phosphate groups for the formation of a phosphorylated intermediate

Substrate specificity

Kinases typically phosphorylates specific target molecules (e.g. proteins, lipids, carbohydrates)

Phosphorylases specifically phosphorylate glycogen or other similar polysaccharides

Functions

Kinases play a vital role in cellular signaling, metabolism, cell division and gene expression

Phosphorylases are involved in regulation of energy metabolism (specifically glycogen breakdown)

Basis of differentiation	Kinases	Phosphorylases
Definition	Kinases refer to enzymes that catalyze the transfer of a phosphate group from ATP or GTP to its protein substrates	Phosphorylases refer to enzymes which catalyze phosphorylation through inorganic phosphates
Addition of phosphate groups	Kinases add phosphate groups to existing organic molecules (does not break the bonds in the substrate)	Addition of phosphate groups by phosphorylases break bonds in the substrate
Regulation	Regulated by phosphorylation	Regulated by phosphorylation or allosteric regulation
Co-substrate requirement	Uses a phosphate group from ATP or GTP for phosphorylation reactions	Uses inorganic phosphate groups as the donor of phosphate groups for the formation of a phosphorylated intermediate
Substrate specificity	Kinases typically phosphorylates specific target molecules (e.g. proteins, lipids, carbohydrates)	Phosphorylases specifically phosphorylate glycogen or other similar polysaccharides
Functions	Kinases play a vital role in cellular signaling, metabolism, cell division and gene expression	Phosphorylases are involved in regulation of energy metabolism (specifically glycogen breakdown)