Biomaterial Database

Protein phosphorylation and metabolic control. 1975

E G Krebs, and J T Stull

The regulation of enzyme activity through the phosphorylation and dephosphorylation of specific seryl or threonyl residues in enzymes is now recognized as an important control mechanism. A great many non-enzymic proteins may also be interconverted between phosphorylated and non-phosphorylated forms, but in these instances the function served by phosphorylation is not well understood. This lack of understanding is probably due to our lack of knowledge of the specialized actions of most non-enzymic proteins. The sequences of phosphorylation and dephosphorylation of proteins are, of necessity, subject to rigid control. If this were not so, the ATP supply of a cell would be rapidly depleted. Moreover, such processes must be regulated for metabolic interconversions to have a physiological regulatory role. For the best studied system, the interconversion of phosphorylase b and phosphorylase a, many different factors controlling the phosphorylation and dephosphorylation steps have been elucidated. Probably this process is constrained so that it uses only a little energy. In this paper, these constraints are examined.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D010750	Phosphoproteins		Phosphoprotein
D010764	Phosphorylase Kinase	An enzyme that catalyzes the conversion of ATP and PHOSPHORYLASE B to ADP and PHOSPHORYLASE A.	Glycogen Phosphorylase Kinase,Phosphorylase b Kinase,Kinase, Glycogen Phosphorylase,Kinase, Phosphorylase,Kinase, Phosphorylase b,Phosphorylase Kinase, Glycogen,b Kinase, Phosphorylase
D010765	Phosphorylase Phosphatase	An enzyme that deactivates glycogen phosphorylase a by releasing inorganic phosphate and phosphorylase b, the inactive form. EC 3.1.3.17.	Glycogen Phosphorylase Phosphatase,Phosphatase, Glycogen Phosphorylase,Phosphatase, Phosphorylase,Phosphorylase Phosphatase, Glycogen
D010770	Phosphotransferases	A rather large group of enzymes comprising not only those transferring phosphate but also diphosphate, nucleotidyl residues, and others. These have also been subdivided according to the acceptor group. (From Enzyme Nomenclature, 1992) EC 2.7.	Kinases,Phosphotransferase,Phosphotransferases, ATP,Transphosphorylase,Transphosphorylases,Kinase,ATP Phosphotransferases
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D006003	Glycogen
D006005	Phosphorylases	A class of glucosyltransferases that catalyzes the degradation of storage polysaccharides, such as glucose polymers, by phosphorolysis in animals (GLYCOGEN PHOSPHORYLASE) and in plants (STARCH PHOSPHORYLASE).	Glucan Phosphorylase,Phosphorylase,alpha-Glucan Phosphorylases