Exam #3

Question 1

SUGARS

Answer 1

MEMORIZE ALL 9 D SUGARS

Question 2

Fischer –> Haworth

Answer 2

C2, C3, C4: right side down, left side up
OH on right: D-sugar
alpha anomer= down @ C1
beta anomer= up @ C1

Question 3

5 ring

Answer 3

furanose

Question 4

6 ring

Answer 4

pyranose

Question 5

Epimers

Answer 5

sugars that differ in chirality at only one stereocenter

Question 6

Starch

Answer 6

alpha 1,4 1,6 glycosidic bonds

Question 7

Amylose

Answer 7

1,4 glycosidic bonds unbranched

Question 8

Amylopectin

Answer 8

1,4 glycosidic and 1,6 glycosidic bonds branched

Question 9

Glucose

Answer 9

1,4 1,6, branch points every 8-12 residues

Question 10

Cellulose

Answer 10

beta 1,4, VdW sheets, chains from hydrogen bonds, unbranched glucose

Question 11

Chitin

Answer 11

beta 1,4 and has N-acetylglucosamine

Question 12

Lysozyme

Answer 12

Would not affect a catalytic mechanism as it has not metal cofactors

Question 13

Enolase

Answer 13

Would affect catalytic mechanism because it strips off 2 Mg2+ metal cofactors to polarize 2-phosphoglycerate to decrease pKa of a proton that will be extracted by K345

Question 14

Glucose-6-Phosphatase

Answer 14

Would not affect catalytic mechanism because there are no metal ion cofactors involved in the catalytic mechanism

Question 15

Pyruvate Decarboxylase

Answer 15

Would not affect catalysis because no metal ion cofactors needed by enzyme for mechanism, EDTA strips off TPP cofactor of enzyme of Mg2+ that stabilizes phosphates. Would not affect catalysis because this portion of TPP is hidden with dimer interface so not exposed to solvent and involved in mechanism

Question 16

Alcohol Dehydrogenase

Answer 16

Would affect catalysis because it would strip Zn2+ held by active site that polarizes carbonyl of acetylaldehyde to make carbonyl carbon electrophilic