3 Biotin Pantacid Flashcards Preview

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Flashcards in 3 Biotin Pantacid Deck (60):
1

Biotin family of vitamins?

B vitamins

2

Biotin is found in

Egg whites

3

Egg White Injury

Eating raw egg white cause deficiency
- dermatitis (rash, red scaley, around eyes, nose and mouth)
- hair loss (thinning or colour loss)
- neurological abnormalities (depression, hallucinations, parethesia of extremities)

4

What bind biotin in raw egg white

Avidin

5

Biotin Structure

bicyclic compound

6

3 structural features of free-biotin

1. ureido ring
2. Sulfer Ring
3. Valeric Acid Sidechain

**OH #9

7

Name of protein bound biotin
- What is bound?

Biocytin
- Boitin plus lysine

8

Biotin binds to enzymes via?

Lysine
(holocarboxylase)

9

In food, biotin is bound to

Proteins

10

What cleaves biocytin from proteins in foods?

Proteases

11

What cleaves Biocytin to form Biotin and Lysine

Biotinidase

12

What inhibits the absorption of biotin?

Avidin

13

What form of biotin is absorbed?

Free biotin (released from lysine)

14

Biotinidase

cleaves biocytin to biotin plus lysine

15

Absorption of biotin occurs?

Intestine

16

3 metabolic functions of biotin

1. part of coenzyme for carboxylases
2. CO2 donor to substrates
3. CO2 fixation reactions

17

4 unique enzymes that depend on Biotin
- what reactions are they involved in?

1. Pyruvate Carboxylase
- glucose metabolism
- gluconeogenesis
- regenerates OAA for TCA cycle

2. Acetyl-CoA Carboxylase
- FA synthesis

3. Propionyl CoA Carboxylase
- source of energy - entry to TCA cycle

4. 3-methylcrotonyl CoA Carboxylase
- AA metabolism; leucin degredation

* ALL carboxylase
**OH 10

18

Holocarboxylase

term to describe biotin-dependent enzymes with biotin attached to them

19

*** Holocarboxylase Synthase

needed to attach biotin to the lysine residue of the enzyme
--> forms holocarboxylase

20

what does TPN stand for?

Total Parenteral Nutrition
- used as solution when body needs nutrients without eating

21

3 causes of biotin deficiency?

decreased intake
decreased absorption (avidin)
Deficiency in enzymes

22

Deficiency in what enzymes would cause biotin deficiency?

Biotinidase
Holocarboxylase Synthase

23

Holocarboxylase Synthase Deficiency propsed to play a role in what other deficiency ?

SIDS
- single carboxylase deficiency
- multiple carboxylase deficiency

24

Problems with "pyruvate carboxylase def" resulting from biotin def?

- decreased gluconeogenesis
- increased pyruvate and lactate (substrates that form glucose)
- less glucose produced

25

Problems with "Acetyl-CoA carboxylase def" resulting from biotin def?

- Acetyl-CoA buildup; risk of ketosis
- Impaired serum lipids

26

Ketosis

Ketone bodies used for energy
- can lead to Ketoacidosis; blood acididty

27

Urinary Metabolites for diagnostics

Accumulate biotin substrates
- beta-methylcrotonate
- beta-hydroxyisovalerate (leucine catabolism intermediate)
- beta-hydroxypropionate
- sometimes lactate

28

Composition tables with Biotin

Not a lot of information about Biotin on composition tables

29

Foods containing biotin

liver
whole grain cereals
nuts, legumes, peanut butter

*litte in fruit/veges
low info on composition tables

30

*** Biotin synthesized in?

*** intestinal bacteria

31

How much biotin can be absorbed?

UNKNOWN

32

T/F
Urine and decal amounts have more biotin than dietary amounts?

True

33

Prebiotic

Promotes probiotics

34

Implications on long term antibiotic use?

- wipe out intestinal bacteria (*** synthesizes biotin)
- digestive health
- pro and prebiotics

35

Biotin requirement affected by?

- amount of raw egg white
- biotinidase deficiency
- drug interactions; anticonvulsants, biotin depletion
- Pregnancy increases requirements
- pro and prebiotics

36

how many biotin dependant enzymes are their?

4 * all end in "carboxylase"

pyruvate, acetyl CoA, propionyl CoA, and 3-methylcrotonyl CoA carboxylase

37

Name of the group of biotin dependent enzymes

holocarboxylase

38

TPN

Total parenteral nutrition

39

Pantothenic Acid absorption

found in many bound forms
intestinal enzymes cleave free pantothenic acid for absorption

(similar to biocytin)

40

Important structural feature of Pantothenic Acid coenzymes structures

SH (thiol) group
- big focus on sulfur

41

***Pantothenic Acid coenzyme forms

Coenzyme A (CoA)
Acyl Carrier Protein (ACP)

both contain SH (thiol) group
* complicated structures

42

Reactions PantAcid coenzymes are involved in

Directly involved biochemical reactions

43

Coenzyme A synthesized from

pantothenic acid
cysteine
ATP

44

CoA alternate abbreviation

CoASH
- stresses the importance of SH

45

Structure features of CoA

* sulfhydryl tail
pantothenic acid
ribose 3-phosphate
adenine

* action happens here

46

Metabolic role of CoA

- Transfers 2 carbon groups (acyl transfer reactions)
- Connects to SH groups
- Central nutrient in metabolism (Acetyl CoA)

(many anabolic/catabolic fates)

47

Anabolic + Catabolic fates of CoA

TCA
cholesterol synthesis
acetylation reactions (drugs)
FA oxidation

48

Vitamin part of CoA

pantothenic acid

49

4 examples of CoA transfering acetyl groups

oxidative decarboxylation (ex. TCA)
- pyruvate --> acetyl CoA
- alpha-ketoglutarate --> succinyl CoA
(other vits involved?)

FA oxidation (beta-oxidation)
- degradation to acetyl-CoA

Ketone body formation

Synthetic Reactions
- cholesterol synthesis HMG CoA

50

Prothetic group

Tightly bound, needed for biological function of protein
- opposed to coenzymes, loosely bound

51

Acyl Carrier Protein (ACP)
- prosthetic group?

Coenzyme form of pantothenic acid
- pantothenic acid is a prosthetic group of ACP

52

Reactive feature of ACP
- where is it from?

SH
- from cysteine

53

ACP part of what enzyme complex?

Fatty acid synthase
- needed for the addition of acyl groups to intermediates to make palmitate

54

Acyl group

O
=
R - C - R

55

Metabolic role of ACP

FA synthesis
- ACP part of FA synthase complex
- acts as a chaperone

ACP added to complex when fat needed (ACP synthetase)
ACP removed fat not needed (ACP hydrolase)

56

What does pentose phosphate pathway produce that is needed for fatty acid synthesis? (Vitamin)

NADPH (Niacin)

(also pentose - don't need to know)

57

Pantothenic Acid food sources

Widespread

-animal sources (liver, meats, milk)
-whole grains
-legumes

58

Pantothenic acid def. side affects

Burning feet syndrome
-WWII prisoners poor nutrition
-pain in toes and feet

not enough known
- found in many foods, deficiency is rare

59

Pantothenic Acid other name

B5

60

Pantothenic acid uses beyond basic nutrition

Wound treatment (oral and topical)

Cholesterol Lowering
- Pantethine (synthetic form)
- Hemodialysis patients (bc of low toxicity level)