Begin is the common term: to begin knitting a sweater. Commence is a more formal word, often suggesting a more prolonged or elaborate beginning: to commence proceedings in court. Initiate implies an active and often ingenious first act in a new field: to initiate a new procedure.
Structure of the trp operon. The trp operon is an operon â a group of genes that are used, or transcribed, together â that codes for the components for production of tryptophan. The trp operon is present in many bacteria, but was first characterized in Escherichia coli.The operon is regulated so that when tryptophan is present in the environment, the genes for tryptophan synthesis are not expressed.It was an important experimental system for learning about gene regulation, and is commonly used to teach gene regulation.he trp operon is present in many bacteria, but was first characterized in Escherichia coli. The operon is regulated so that when tryptophan is present in the environment, the genes for tryptophan synthesis are not expressed.
1 Tryptophan 2,3-dioxygenase (TDO) is important for regulating the levels of tryptophan in the body and is expressed in a high number of human tumors. 2  The other heme iron-dependent dioxygenase, IDO, also has relevance to human health, as it functions in inflammatory responses in the context of certain diseases.he ability of these dioxygenases to retain activity in the presence of other metal cofactors with wide ranges of redox potentials suggests the metal center does not play an active role in the activation of dioxygen.