Nutritional Biochemistry - Water soluble vitamins

Vitamin B1 (thiamine)

Anti-beriberi, anti-neuritic, morale vitamin

Thiamin (B1)

Helps the body release energy from food, promotes normal appetite, and helps the nervous system. Present as TPP involved in (de)carboxylation reactions

Thiaminase

Thiamin antagonist present in raw seafood and shellfish

chlorogenic acid and tannins

Thiamin antagonists present in coffee and tea

Pork

Richest source of Thiamin

Thiamine

Water soluble vitamin which aids conversion of tryptophan to niacin

Dry Beri Beri

associated with nervous system and results in muscle weakening in legs and arms, parathesia, and numbness

Wet beriberi

Form of beriberi characterized by high output cardiac failure (dilated cardiomegaly), edema

Infantile beriberi

Observed in breastfed infants whose mothers are thiamin deficient

Wernicke-Korsakoff syndrome

a condition caused by deficiencies in thiamine secondary to alcohol dependence (alcoholism)

Riboflavin (B2)

In its active form as a flavoprotein, it is involved in macronutrient metabolism

Thiamine pyrophosphate (TPP)

Active coenzyme form of thiamine

Diets consisting of primarily refined grains

Dietary risk factor for thiamine, riboflavin deficiencies

FAD and FMN

Active coenzyme forms of riboflavin (acronym)

FAD and FMN

Storage form of riboflavin

xanthine oxidase

A FAD-dependent enzyme responsible for the conversion of hypoxanthine to xanthine to uric acid

riboflavin, pyridoxine, folate, cobalamin

Four (4) B vitamins with roles in homocysteine metabolism

angular stomatitis

inflammation and cracking at the corners of the mouth; a symptom of riboflavin deficiency

cheilitis

Inflammation of the lips. A symptom of riboflavin deficiency

glossitis

inflammation of the tongue; riboflavin deficiency

Nasolabial dyssebacea

Disorder of sebaceous glands of the nose and mouth region characterized by reddening and flaking of skins

corneal vascularization

Abnormal condition characterized by blood vessel growth in the cornea; present in riboflavin deficiency

Milk, liver, and egg

Richest source of riboflavin

1.3 mg/day

RDA of riboflavin for filipino adult males

1.1 mg/day

RDA of riboflavin for filipino adult females

Free riboflavin

Excretion form of riboflavin

Niacin (B3)

The pellagra-preventive, anti-black tongue factor

Vitamers

Members of the same family of vitamins; same biologic activity but different biopotency

60 mg tryptophan

The amount of tryptophan needed to synthesize 1 mg of niacin

Nicotinic Acid (Niacin), Niacinamide

Two (2) forms of niacin

> 1-3 g

Pharmacologic dose of nicotinic acid used in treatment of hypercholesterolemia

Yeast

Richest source of niacin

NAD+ and NADP+

Active coenzyme forms of niacin (acronym) which serves as electron acceptors and donors

Pellagra

A clinical condition brought about by severe niacin deficiency

Dermatitis, dementia, diarrhea, and death

4 D Characteristics of Pellagra

Pyridine and methyl nicotinamide

Compounds measured in urine for assessment of niacin status

Pantothenic Acid (B5)

The anti-chromotrichial factor, pantothenol, and pantotheine

calcium pantothenate

Synthetic derivative in crystal form used in nutritional supplements

Omega-methylpantothenic acid, pentoyl taurine, and phenylpantothenate

Antagonists of pantothenic acid

Liver

Richest source of pantothenic acid

Coenzyme A (CoA)

Coenzyme to which pantothenate serves as a component/prosthetic group. Used in acetylation reactions

Pantothenic Acid (B5)

Vitamin necessary for production of acetylcholine, a neurotransmitter affecting muscles

Pantheine

A form of B5 which normalized blood lipid profiles

burning feet syndrome

clinical symptom associated with pantothenic acid deficiency

Pyridoxine (B6)

A B vitamin needed in the synthesis of dopamine, acetylcholine, and seratonin

Pyridoxine phosphate (PLP)

Coenzyme form of pyridoxine (B6) involved in urea and protein metabolism i.e. deamination and transamination reactions

pyridoxine, pyridoxal, pyridoxamine

Dietary forms of pyridoxine

Deoxypyridoxine, methoxypyridoxine, toxopyrimidine

Antagonists of pyridoxine

Isoniazid (INH)

A drug which is a vitamin antagonist of pyridoxine

Liver and glandular organs

Richest source of pyridoxine

Folate

a B vitamin that is essential for cell growth and reproduction; pteroylglutamic acid, L. casei factor

1.7 ug DFE

The equivalent dietary folate equivalent (DFE) of 1 ug folic acid taken with meal

2.0 ug DFE

The equivalent dietary folate equivalent (DFE) of 1 ug folic acid not taken with meals

Conjugase or Folate hydrogenase

A lysosomal enzyme which hydrolyses glutamic scid residues of folate

polyglutamate form

Stored predominant THF form in liver; More active form of folate

Tetrahydrofolate (THF)

Coenzyme form of folate which serves as donors of one-C units in a number of biologic reactions such as in homocysteine metabolism and choline synthesis

Folate

Antivitamin of zinc

Low green leafy vegetable and legume intake

Dietary risk factor for inadequate folate intake

Amethopterin, aminopterin, tetrahydroaminophen, ptyrolaspartic acid

Folate antagonists

Methionine synthetase

An enzyme requiring cobalamin which renders the folate coenzyme to function via releasing it from the methyl-THF form

neural tube defects

spina bifida and anencephaly

Folate deficiency

Nutritional deficiency associated with neural tube defects

B12 deficiency

Another nutritional deficiency which can lead to folate deficiency

megaloblastic anemia

a blood disorder characterized by anemia in which the red blood cells are larger than normal (macrocytic)

400 ug DFE

Adult RDA of folate

+200 ug RE

Addition to RDA of during pregnancy

Dark green leafy vegetables

Richest source of folate

Cobalamin

Anti-pernicious anemia, erythrocyte maturation factor

corrinoids

B12 consists of a group of compounds called ____ due to their corrin nucleus with cobalt centers

methylcobalamin, 5-deoxyadenosylcobalamin

the coenzyme forms of B12

Cyanocobalamin

Pharmaceutical form of B12 used in supplements

R-binder

Salivary peptide which binds to B12

Intrinsic Factor (IF)

A glycoprotein secreted by the stomach that results in the absorption of vitamin B12 upon binding

Transcobalamin I, II, and III

Transport proteins which carry B12

B12-protein complex

Storage form of B12 in liver and kidney

Pyridoxine deficiency

A water-soluble vitamin deficiency which decreases gastric secretions, resulting to depressed cobalamin absorption.

pernicious anemia

an autoimmune diseases characterized by a lack of mature erythrocytes caused by inability to absorb vitamin B12 into the bloodstream due to IF deficiency. Erythrocytes are hyperchromic and macrocytic

Streptomyces griseus

Commercial source of vitamin B12

Myelin

Lipoprotein substance in nerve fibers which requires vitamin B12 for synthesis

pernicious anemia

an autoimmune diseases characterized by a lack of mature erythrocytes caused by inability to absorb vitamin B12 into the bloodstream due to IF deficiency. Erythrocytes are hyperchromic and macrocytic

Streptomyces griseus

Commercial source of vitamin B12

Myelin

Lipoprotein substance in nerve fibers which requires vitamin B12 for synthesis

Biotin

Also called the anti-egg white injury factor

Thiamine, biotin, and pantothenate

Three (3) sulfur-containing B vitamins

Biocytin

a biotin-lysine complex released from digested protein. Produced by imtestinal bacteria

Avidin

A protein in raw egg whites that binds and inactivates biotin

Carboxylases

the enzymes which requires biotin as a coenzyme

Biotinidase

An enzyme in the small intestine that releases biotin from food to allow it to be absorbed.

Aspartic acid, threonine, and serine (A-S-T)

Three amino acids to which biotin has a role in their deamination reaction

Increase

Alcohol consumption, pregnancy, use of sulfonamide drug and antibiotics, diarrhea, lactation, fever, surgery, and excessive intake of sugar and carbohydrates are factors which __________ thiamin requirement

Decrease

Increased fat intake is a factor which __________ thiamin requirement

Na-dependent active transport; passive diffusion, if at large amounts

The mechanism of absorption for thiamine

Active transport

The mechanism of absorption for riboflavin

carrier-mediated facilitated diffusion

The mechanism of absorption for niacin at low concentrations

diffusion

The mechanism of absorption for niacin at high concentrations

passive diffusion

The mechanism of absorption for pyridoxine

Alkaline phosphatase

An enzyme which is found in the intestinal lumen which dephosphorylates pyridoxine for absorption

Aldehyde oxidase

An enzyme which is found in the liver which converts pyridoxal to pyridoxic acid

Glycogen phosphorylase

In muscles, most pyridoxal phosphate is bound to this enzyme

Carpal tunnel syndrome

A condition caused by compression of the median nerve in the carpal tunnel and characterized especially by weakness, pain, and disturbances of sensation in the hand and fingers. Pyridoxine therapy is used to alleviate its symptoms