Kinase Activity
In biochemistry, a kinase is a type of enzyme that transfers phosphate groups (see below) from high-energy donor molecules, such as ATP (see below) to specific target molecules (substrates); the process is termed phosphorylation. The opposite, an enzyme that removes phosphate groups from targets, is known as a phosphatase. Kinase enzymes that specifically phosphorylate tyrosine amino acids are termed tyrosine kinases.
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Phosphate -
ATP -
Tyrosine
When a growth factor binds to the extracellular domain of an RTK, its dimerization is triggered with other adjacent RTKs. Dimerization leads to a rapid activation of the protein's cytoplasmic kinase domains, the first substrate for these domains being the receptor itself. The activated receptor as a result then becomes autophosphorylated on multiple specific intracellular tyrosine residues.
Read more about this topic: Receptor Tyrosine Kinases
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“The Good of man is the active exercise of his soul’s faculties in conformity with excellence or virtue.... Moreover this activity must occupy a complete lifetime; for one swallow does not make spring, nor does one fine day; and similarly one day or a brief period of happiness does not make a man supremely blessed and happy.”
—Aristotle (384–322 B.C.)