41. Response regulators are coupled to specific histidine kinases which serve as sensors of environmental changes. 42. It is an inhibitor of histidine decarboxylase. 43. It uses the recommended OECD Guideline 471 tester strains ( histidine auxotrophs and tryptophan auxotrophs ). 44. In plants, VirA is a protein histidine kinase which senses certain sugars and phenolic compounds. 45. DEPC derivatization of histidines is also used to study the importance of histidyl residues in enzymes. 46. The equivalent Serine-Histidine -" Glutamate " triad is used in acetylcholinesterase. 47. This Histidine is bound to the Type 2 Cu center responsible for binding and reducing nitrite. 48. These histidines all work in conjunction to keep the heptamer from inserting prematurely before endocytosis occurs. 49. The zinc coordination sphere is composed of three histidines , one aspartate and two water molecules. 50. This enzyme participates in histidine metabolism.
