Enzyme defect tested in Guthrie’s test?
Correct Answer: Phenyl alanine hydroxylase
Description: Ans. is 'a' i.e., Phenyl alanine hydroxylase* Guthrie's test is done to detect Phenylketonuria. Phenylketonuria is caused by a defect of phenylalanine hydroxylase.* It was devised by Dr Robert Guthrie after the birth of his own child with PKU.* It is based on the fact that an organism Bacillus subtilis needs phenyl ketone for its growth.* A small drop of blood is taken from the heel of a newborn and applied to a card. A punch-out dried disc from the card is then incubated on a petri dish plated with bacteria (Bacillus subtilis) in the presence of a growth inhibitor, B-2-thienyl-alanine. High levels of phenyl ketone in the blood sample overcome the inhibition, and allow the bacteria to grow. So, a colony count of the plate will give us an approximate concentration of phenyl ketone inthe blood.* However, this test has been replaced by HPLC with Tandem Mass spectrometry
Category:
Biochemistry
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now