Regulation of phosphorylase a is completed by phosphorylation. However, this covalent modification increases or decreases activity without completely inhibiting it. The velocity plot is sigmoidal. What statement can be made about this enzyme?

Allosteric regulation, extensively, is only any type of regulation where the regulatory molecule (an activator or inhibitor) ties to a protein somewhere other than the dynamic site. Where the controller ties is known as the allosteric site.
Essentially all cases of noncompetitive restraint (alongside some novel instances of serious hindrance) are types of allosteric regulation.
A few chemicals that are allosterically controlled have a lot of one of a kind properties that set them apart. These compounds, which incorporate a portion of our key metabolic controllers, are regularly given the name of allosteric enzymes
Allosteric enzymes commonly have various active sites situated on various protein subunits. At the point when an allosteric inhibitor binds to a enzyme, every single dynamic site on the protein subunits are changed slightly so they work less well.
There are also allosteric activators. Some allosteric activators tie to areas on a chemical other than the dynamic site, causing an expansion in the capacity of the dynamic site. Additionally, in a procedure called cooperativity, the substrate itself can fill in as an allosteric activator: when it ties to one dynamic site, the action of the other dynamic destinations goes up. This is considered allosteric regulation in light of the fact that the substrate influences dynamic locales a long way from its coupling site.