PKU Disease. Stephanie Inskeep Junior Biochemistry Major Spring 2009. Background. Inherited disease Lack of the enzyme phenylalanine hydroxylase (PAH) Catalyzes first step in the degradation of phenylalanine Phenylalanine transaminated to phenylpyruvate, a phenylketone compound
Junior Biochemistry Major
A short time after administering a measured amount of phenylalanine to the subject, the concentration of phenylalanine in the blood plasma is measured. The level is usually substantially higher in people who carry one PKU gene (even though they show no signs of disease) than in individuals who are homozygous for the unmutated gene. Both parents must be heterozygous (must be carriers of the trait to produce a child with PKU disease (1 in 4 chance)
In the course of oxidizing phenylalanine to tyrosine, the enzyme PAH also oxidizes BH4 to BH2 (dihydrobiopterin). The necessary BH4 must then be regenerated by the action of a separate enzyme, dihydropteridine reductase (DHPR).
2.) Tyrosine involved in depression, eating, memory, sleep, it is even involved in which way you turn more – left or right) it’s pretty important to have. So people with PKU have to eat more food high in tyrosine to replace their lack of phenylalanine.
3.) The biochemical defect in albinism appears to be the absence of the enzyme tyrosinase, which prevents the synthesis of melanin pigment by pigment-forming cells. These individuals have a very white skin, fine white hair, pink or light blue irises of the eyes, and a variety of other eye disturbances