Zinc

Question 1

Biochem function- catalytic

Answer 1

components of Zn containing metalloenzyme (~100 enzymes)
alcohol dehydrogenase, Zn- Cu superoxide dismutase (SOD)

• ALS/Lou Gehrig’s is mutation of SOD

Question 2

Biochem function- structural

Answer 2

zinc fingers. proteins on DNA, sites for binding transcription factors

Question 3

Biochem function- regulatory

Answer 3

regulator of gene expression
metal response element (MRE) binding transcription factor (metallothionine gene)
zinc regulates hormones and enzyme secretions
insulin, digestive enzymes, acid

Question 4

Zn containing enzymes– alcohol dehydrogenase

Answer 4

Alcohol dehydrogenase. facilitates, interconversion between alcohols, aldehydes, or ketones w/ reduction of NAD+ –> NADH

Question 5

Zn containing enzymes– carbonic anhydrase

Answer 5

carbonic anhydrase. catalyze rapid interconversion of CO2 + H2O –> bicarbonate + proteins.
reversible

Question 6

Zn containing enzymes– SOD

Answer 6

Reduction of Cu, oxidation of Superoxide,
Reduction of Superoxide, Cu.
just need to stabilize O2- –> O2 or H2O2

Question 7

Absorption

Answer 7

transport into enterocyte. Zip proteins (+) Zn transport from ECF –> cytoplasm.

Zip 4 found in intestinal brush border. paracellular Zn absorption by diffusion when given zinc salts as supplement

Question 8

Absorption– Intracellular factors

Answer 8

Metallothionein MT –> Cys rich, low molecular weight of golgi complex in enterocytes
MT is intracellular metal buffer by binding heavy metals (Zn, Cu), regulates amount of metal released into circulation.

Question 9

Absorption– Export from enterocyte

Answer 9

mediated by ZnT proteins that lower ICF zinc by moving it out of cells

• • Zip= Zrt + Irt- like solute linked carrier 39A (SLC39A) protein
• • ZnT is Zn transporter SLC30A

Question 10

low zinc

Answer 10

(+) Zip4 expression –> inc Zn absorption

Question 11

adequate/ inc zinc

Answer 11

(+) MT –> sequesters Zn/Cu inside intestinal cell

Question 12

low extracellular zinc

Answer 12

(+) ZnT

Question 13

static indices

Answer 13

plasma/ serum Zn concentrations

Question 14

functional indices

Answer 14

Zn dependent enzyme activity, taste acuity, immune status

Question 15

Zn/phytate ratio

Answer 15

phytates bind zinc, (-) absorption. amount of observable Zn related to molar ratio

<5= 45-55% Zn absorbed
5-15= 30-35%
>15= 10-15%

Question 16

Zn –> Cu status

Answer 16

inc Zinc (+) MT –> sequesters Zn/Cu inside enterocyte –> loss in feces

Question 17

sideroblastic anemia

Answer 17

hypochronic, microcytic, disorder of bone marrow –> Cu deficiency

low Cu –> low ceruloplasmin (Fe2+ –> Fe3+ for Hgb formation), –> Low RBC Cu/Zn SOD –> low RBC lifespan

Question 18

deficiency

Answer 18

vegetarian, pregnant, lactating, older infants, sickle cell, alcoholics

Question 19

current issues

Answer 19

immune function, wound healing, acute diarrhea, common cold, age related macular degeneration