HIS108 Lecture Notes - Lecture 1: Probiotic, Galactosemia, Epimerase And Racemase
Document Summary
Leloir pathway: galactokinase phosphorylates galactose, gal-1-p uridyltransferase converts galactose-1-p to glucose-1-p, udp-gal epimerase converts udp-galactose (product of second enzyme) to udp- ~65% of humans have reduced ability to digest lactose after weaning: humans follow same trend as shown with rabbits. Mutations that keep lactase gene permanently on: arose randomly in adjacent regulatory gene (mcm6) and once it arose gave distinct advantages to these populations (enhances lct transcription, due to ancestry that consumed a lot of lactose. Lactase non-persistence: gene is regulated at a lower level, can still consume moderate amounts in diet without experiencing any difficulties. Note: lct gene on chromosome 2 codes for lactase enzyme. Note: prokaryotic cells can break lactose down in the large intestine because they have. Galactosadase and lactose permease that can digest lactose but they produce gasses leading to bloating, gas, cramps, etc. Inherited mutations by the galt, gale galk1 and genes on chromosomes 9 short: almost completely eliminate enzyme activity.
