Proteins III

Question 1

catalyzes rxn of pyruvate lactate

Answer 1

Lactate dehydrogenase (LDH)

Question 2

Protein isoform with two subunits:

Answer 2

M(muscle) and H(heart)

Question 3

Higher than normal levels of H4 in the blood may suggest ______

Answer 3

myocardial infarction (heart attack)

Question 4

Occurs via glycosyltransferases; it begins in the Endoplasmic reticulum and ends in the Golgi complex and is usually present on secreted protein such as TSH, LH, hCG, or membrane proteins.

Answer 4

Glycosylation of proteins

Question 5

Function in proper folding of transmembrane proteins, structural stability, and recognition for cell adhesion.

Answer 5

Glycoproteins

Question 6

Changes in HbA1c can be used to track effectiveness of

Answer 6

Diabetes treatment over the course of 4 months.

Question 7

Protein acetylation promotes

Answer 7

resistance to degradation of proteins while in the cell.

Question 8

Acetylation and Methylation contribute to the _______ and epigenetics which helps control gene expression in eukaryotes.

Answer 8

“Histone Code”

Question 9

A way to anchor proteins to the cell membrane via acylation with myristoyl (C14) or palmitoyl (C16) groups; or prenylation with farnesyl (C15) or geranylgeranyl (C20) groups; or glycosylphosphatidylinositol (GPI) anchor.

Answer 9

Lipidation

Question 10

Phosphorylation uses

Answer 10

kinases and phosphatases

Question 11

Catalyzed by hydroxylases; seen in collagen and elastin

Answer 11

Hydroxylation

Question 12

Requires vitamin K as a coenzyme; seen with glutamic acid in blood clotting factors. Resulting “Gla” proteins readily chelate Calcium.

Answer 12

Carboxylation

Question 13

An erythrocyte (RBC) integral membrane protein.

Answer 13

Glycophorin

Question 14

Can only be removed from the cellular membrane with detergents

Answer 14

Integral proteins

Question 15

More loosely associated to the membrane

Answer 15

peripheral proteins

Question 16

Three types of membrane transport proteins

Answer 16

Pumps, channels, transporters

Question 17

Use energy released from ATP hydrolysis (ATP ADP +Pi) to move specific ions against an electrochemical gradient

Answer 17

Pumps

Question 18

Allow the movement of ions down their electrochemical gradient (i.e passive transport).

Answer 18

Channels

Question 19

Facilitate movement of specific small molecules or ions by going thru a conformational change.

Answer 19

Transporters

Question 20

Transport down its concentration gradient

Answer 20

Uniporters

Question 21

Move one molecule against its concentration gradient; while driving one or more ions down their concentration gradient.

Answer 21

Symporters and antiporters

Question 22

The largest cell surface receptors

Answer 22

G protein coupled receptors

Question 23

The major sorting center of the cell

Answer 23

Golgi complex

Question 24

Protein path

Answer 24

Proteins travel from ribosomes (on rough ER)  Golgi  proper destination

Question 25

Due to a series of hydrolytic enzymes being delivered to the wrong cell; as a result, there are high levels of these proteins in blood and urine and the lysosomes contain large inclusions of undigested glycosaminoglycans and glycolipids

Answer 25

I-cell disease (aka mucolipidosis II) Symptoms: psychomotor retardation and skeletal deformities Mechanism: Normally the enzymes contain mannose-6-phoshpate residue, but mannose-6-phoshate remains unphosphorylated and the enzyme is not able to direct hydrolytic enzymes from the Golgi to the lysosome.

Question 26

N-linked or O-linked ______ of AA with distal amino (Arg, Lys) or carboxyl (Asp, Glu) groups. Amino groups may be mono-, di-, or tri-substituted.

Answer 26

methylation

Question 27

Membranes vary in protein content: myelin sheath ____%; plasma membrane____%; mitochondrial membrane _____%

Answer 27

18; 50; 75

Question 28

TM proteins have three parts:

Answer 28

extracellular, membrane-spanning, and cytoplasmic

Question 29

Answer 29

Question 30

Thermal and chemical (except ____) denaturation usually reversible

Answer 30

SDS