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)

3 Biotin Pantacid Flashcards by Ben Holtom

Biotin family of vitamins?

B vitamins

How well did you know this?

Not at all

Perfectly

Biotin is found in

Egg whites

How well did you know this?

Not at all

Perfectly

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)

How well did you know this?

Not at all

Perfectly

What bind biotin in raw egg white

Avidin

How well did you know this?

Not at all

Perfectly

Biotin Structure

bicyclic compound

How well did you know this?

Not at all

Perfectly

3 structural features of free-biotin

ureido ring
Sulfer Ring
Valeric Acid Sidechain

**OH #9

How well did you know this?

Not at all

Perfectly

Name of protein bound biotin

- What is bound?

Biocytin

- Boitin plus lysine

How well did you know this?

Not at all

Perfectly

Biotin binds to enzymes via?

Lysine

holocarboxylase

How well did you know this?

Not at all

Perfectly

In food, biotin is bound to

Proteins

How well did you know this?

Not at all

Perfectly

What cleaves biocytin from proteins in foods?

Proteases

How well did you know this?

Not at all

Perfectly

What cleaves Biocytin to form Biotin and Lysine

Biotinidase

How well did you know this?

Not at all

Perfectly

What inhibits the absorption of biotin?

Avidin

How well did you know this?

Not at all

Perfectly

What form of biotin is absorbed?

Free biotin (released from lysine)

How well did you know this?

Not at all

Perfectly

Biotinidase

cleaves biocytin to biotin plus lysine

How well did you know this?

Not at all

Perfectly

Absorption of biotin occurs?

Intestine

How well did you know this?

Not at all

Perfectly

3 metabolic functions of biotin

part of coenzyme for carboxylases
CO2 donor to substrates
CO2 fixation reactions

How well did you know this?

Not at all

Perfectly

4 unique enzymes that depend on Biotin

- what reactions are they involved in?

Pyruvate Carboxylase
- glucose metabolism
- gluconeogenesis
- regenerates OAA for TCA cycle
Acetyl-CoA Carboxylase
- FA synthesis
Propionyl CoA Carboxylase
- source of energy - entry to TCA cycle
3-methylcrotonyl CoA Carboxylase
- AA metabolism; leucin degredation

ALL carboxylase
*OH 10

How well did you know this?

Not at all

Perfectly

Holocarboxylase

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

How well did you know this?

Not at all

Perfectly

*** Holocarboxylase Synthase

needed to attach biotin to the lysine residue of the enzyme

–> forms holocarboxylase

How well did you know this?

Not at all

Perfectly

what does TPN stand for?

Total Parenteral Nutrition

- used as solution when body needs nutrients without eating

How well did you know this?

Not at all

Perfectly

3 causes of biotin deficiency?

decreased intake
decreased absorption (avidin)
Deficiency in enzymes

How well did you know this?

Not at all

Perfectly

Deficiency in what enzymes would cause biotin deficiency?

Biotinidase

Holocarboxylase Synthase

How well did you know this?

Not at all

Perfectly

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

SIDS

single carboxylase deficiency
multiple carboxylase deficiency

How well did you know this?

Not at all

Perfectly

Problems with “pyruvate carboxylase def” resulting from biotin def?

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

How well did you know this?

Not at all

Perfectly

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

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

Ketosis

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

Urinary Metabolites for diagnostics

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

Composition tables with Biotin

Not a lot of information about Biotin on composition tables

Foods containing biotin

liver whole grain cereals nuts, legumes, peanut butter *litte in fruit/veges low info on composition tables

*** Biotin synthesized in?

*** intestinal bacteria

How much biotin can be absorbed?

UNKNOWN

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

True

Prebiotic

Promotes probiotics

Implications on long term antibiotic use?

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

Biotin requirement affected by?

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

how many biotin dependant enzymes are their?

4 * all end in "carboxylase" pyruvate, acetyl CoA, propionyl CoA, and 3-methylcrotonyl CoA carboxylase

Name of the group of biotin dependent enzymes

holocarboxylase

TPN

Total parenteral nutrition

Pantothenic Acid absorption

found in many bound forms intestinal enzymes cleave free pantothenic acid for absorption (similar to biocytin)

Important structural feature of Pantothenic Acid coenzymes structures

SH (thiol) group | - big focus on sulfur

***Pantothenic Acid coenzyme forms

``` Coenzyme A (CoA) Acyl Carrier Protein (ACP) ``` both contain SH (thiol) group * complicated structures

Reactions PantAcid coenzymes are involved in

Directly involved biochemical reactions

Coenzyme A synthesized from

pantothenic acid cysteine ATP

CoA alternate abbreviation

CoASH | - stresses the importance of SH

Structure features of CoA

* sulfhydryl tail pantothenic acid ribose 3-phosphate adenine * action happens here

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)

Anabolic + Catabolic fates of CoA

TCA cholesterol synthesis acetylation reactions (drugs) FA oxidation

Vitamin part of CoA

pantothenic acid

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

Prothetic group

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

Acyl Carrier Protein (ACP) | - prosthetic group?

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

Reactive feature of ACP | - where is it from?

SH | - from cysteine

ACP part of what enzyme complex?

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

Acyl group

O = R - C - R

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)

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

NADPH (Niacin) | also pentose - don't need to know

Pantothenic Acid food sources

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

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

Pantothenic Acid other name

Pantothenic acid uses beyond basic nutrition

Wound treatment (oral and topical) Cholesterol Lowering - Pantethine (synthetic form) - Hemodialysis patients (bc of low toxicity level)