Lecture 35

Question 1

A ________ kinase deficiency leads to buildup of Galactose (Galactosemia.) At high levels, Galactose can be acted upon by ________ reductase (which has a high Km for Galactose) to form Galactitol. Galactitol build up can cause _______ in the eye.

Answer 1

A Glactose Kinase deficiency leads to buildup of Galactose. At high levels, Galactose can be acted upon by Aldose reductase to form Galactitol. Build up of Galactitol can cause CATARACTS.

Question 2

Classic Galactosemia is more sever than that caused by a Galactose Kinase deficiency. In classic Galactosemia, ______ is deficient, causing a buildup of _______ in the cell, rather than converting it to UDP-_______. Buildup of _______ can cause ______ damage, ______ disability, ______ in the eye, and premature _______ failure in females.

Answer 2

Galactose-1-P uridyltransferase is deficient, causing a buildup of Galactose-1-P, rather than converting it to UDP-Glucose. Buildup of Galactose-1-P can cause LIVER damage, LEARNING disability, CATARACTS, and premature OVARIAN failure in females.

Question 3

Glycogen is the storage form of Glucose with glucosyl residues linked via a(n) ______ glycosidic bond and _______ linkage at branch points (increasing the solubility of glycogen) occurring about every 8-12 _______ glycosidic bonds.

Answer 3

Glucosyl residues linked via an ALPHA 1,4 glycosidic bond and ALPHA 1,6 linkage at branch points (increasing the solubility of glycogen) occurring every 8-12 ALPHA 1,4 bonds.

Question 4

_____ catalyzes the reaction that adds _____ onto glycogen via the formation of an alpha-1,4 linkage, and glycogen ______ enzyme catalyzes the alpha-1,6 linkages.

Answer 4

Glycogen synthase catalyzes the reaction that adds UDP-GLUCOSE onto glycogen, and glycogen BRANCHING enzyme catalyzes the alpha-1,6 linkages.

Question 5

Glycogen is a glycoprotein that uses ______ which lays down a “primer” so that Glycogen Synthase can add UDP-glucose to the chain.

Answer 5

It uses GLYCOGENIN

Question 6

Glycogen ______ is the enzyme that catalyzes the cleavage of alpha-1,4 linkages, which require inorganic ______ and forms ______-1-phosphate.

Answer 6

Glycogen PHOSPHORYLASE is the enzyme that catalyzes the cleavage, which requires inorganic PHOSPHATE and forms GLUCOSE-1-Phosphate.

Question 7

Branch points are cleaved by a ______ reaction catalyzed by _______ enzyme to produce free _____. This enzyme also has _______ activity, transferring small oligosaccharides near branch points to alpha-1,4 linked chains.

Answer 7

Cleaved by a HYDROLYTIC reaction catalyzed by GLYCOGEN DEBRANCHING enzyme to produce free GLUCOSE. Also has TRANSFERASE activity.