Nutritional Biochemistry Flashcards
What are the two types of carbohydrate transporters?
SGLT1 – absorbs glucose and galactose
GLUT5 – transports fructose
What are some vitamins involved in the pathway that takes pyruvate to acetyl-CoA?
TPP - Thiamine Pyrophosphate
FAD - Flavin Adenine Dinucleotide (Riboflavin)
NAD - Nicotinamide Adenine Dinucleotide (Niacin)
- Cofactor for pyruvate dehydrogenase–decarboxylation
- Cofactor in pentose phosphate pathway–NADPH
- Maintains neural membranes and normal nerve conductions–pH, myelin, neurotransmitters
Thiamine/Vitamin B1
Deficiency of Thiamine
Polyneuropathy – Dry Beriberi
Dilated cardiomyopathy – Wet Beriberi
Wernicke-Korsakoff syndrome
- Coenzyme A–Amino acid, carbo, fat and nucleic acid metabolism
- Acyl carrier protein–fatty acid synthesis
Pantothenic acid/Vitamin B5
Deficiency of pantothenic acid/vit B5
Dermatitis
Enteritis
Alopecia
Adrenal insufficiency
Active forms of Riboflavin/Vitamin B2
Flavin mononucleotide (FMN) Flavin adenine dinucleotide (FAD)
Acts as an electron carrier for complex dehydrogenases and for the citric acid cycle to electron transport chain
Riboflavin/Vitamin B2
Deficiency of Riboflavin/Vitamin B2
Cheilosis (scaling and fissures at the corner of the mouth)
Dermatitis
Corneal neovascularization
What are some sources of niacin/vitamin B3?
Diet
Synthesized from tryptophan
Active forms of Niacin?
NAD+: carbohydrate, fat, amino acids and nucleic acid degradation, citric acid cycle
NADH: citric acid cycle –> electron transport chain
NADP+: Glucose-6-phosphate dehydrogenase in the pentose phosphate shunt
NADPH: Used in synthesis of carbohydrates, fats, amino acids and nucleic acids
Deficiency in Niacin/Vitamin B3?
Glossitis
Pellagra
Active forms of Biotin/Vitamin B7?
Biotin bound to carboxylases
Released by biotinidase in small intestine
Bound in cells to carboxylases
Carboxylase cofactor–binds CO2
For pyrovate carboxylase
Acetyl CoA carboxylase
Biotin/Vitamin B7
Deficiency of biotin/vitamin B7
Dermatitis
Hair loss (alopecia)
Enteritis
Active form of pyridoxine/Vitamin B6
Pyridoxal phosphate
Coenzyme involved in amino acid degradation/conversion to other important molecules
-Aminotransferases
-Decarboxylases–serotonin, norepi
-Serin hydroxymethyltransferase – one carbon metabolism/myelination
-Aldolases
Coenzyme involved in glycogen degradation
-Glycogen phosphorylase
Coenzyme involved in porphyrin synthesis
Pyridoxin/Vitamin B6
Deficiency in Pyridoxin/Vitamin B6
Convulsions
Dermatitis
Peripheral neuropathy
Sideroblastic anemia
Active form of Folate/Vitamin B9
Tetrahydrofolate
Carrier of 1 carbon units for purine synthesis, dTMP synthesis from dUMP and conversion of homocysteine to methionine for S-adenosylmethionine synthesis
Folate/Vitamin B9
Deficiency of Folate/Vitamin B9
Megaloblastic anemia
Fetal neural tube defects
How is Cobalamin/Vitamin B12 absorbed?
Through an Intrinsic factor – Vitamin B12 complex
Cofactor for methionine synthase and methylmalonyl-CoA mutase
Required fro TH4 Folate availability for DNA synthesis
Functions in myelin synthesis
Cobalamin/Vitamin B12
Deficiency of Cobalamin/Vitamin B12
Megaloblastic anemia
Fetal neural tube defects
Demyelination
Neural degeneration
Where are most B-vitamins absorbed?
Duodenum
Jejunum
Where is B12 absorbed?
Ileum
Where is microbiota produced biotin absorbed?
Large intestine
Active form of Ascorbate/Viatmin C
Ascorbic acid
Antioxidant
Cofactor of enzymes that reduce metal ions
Post-translational modification of proteins–collagen
Synthesis of ntm and hormones
Ascorbate/Vitamin C
Deficiency of Vitamin C
Abnormal collagen cross linking leading to bleeding
Scurvy
Where is vitamin E/tocopherol stored?
In adipose tissue, liver, muscle
Antioxidant-scavenges free radicals
Recycled by Vitamin C
Vitamin E/Tocopherol
Deficiency of Vitamin E/Tocopherol?
Hemolytic anemia
Muscle weakness
Demyelination
Cofactor for coagulation factors 2, 7, 9, 10, protein C and protein S; also for bone calcium binding proteins
Modified Gla residue binds calcium, localizes to activated platelets
Vitamin K/Phylloquinone
Deficiency of vitamin K/phylloquinone?
Bleeding
Where is vitamin A stored?
Liver
Active forms of vitamin A and what they are used for
Beta-carotene: antioxidant, vit A precursor
Retinol (vit a): major transport form
11-cis retinal (retinaldyhyde): vision
Retinoid acid: gene regulation
What are some things that retinoid acid regulates the gene expression of?
Epithelial cell function Mucous cell function Immunity Reproduction Development
Deficiency of Vitamin A (carotenes, retinoids)
Night blindness Susceptibility to infection Dry scaly skin Corneal degeneration Alopecia Oseoporosis
What does 11-cis-retinal bind?
Rhodopsin in rods
Cone pigments in cones
Forms of vitamin D/Calciferols
Dietary in micelles: Cholecalciferol (animals), ergocalciferol (plants)
Hormone: 7-dehydrocholesterol –> vitamin D2
Active: 1, 25 dihydroxyvitamin D
Controls expression genes that act in calcium and phosphate absorption in the intestine, bone formation and dissolution, renal retention of calcium and phosphate
Also: cell cycle arrest, apoptosis, immune suppression, anti-inflammation, differentiation
Requires retinoic acid
Vitamin D/Calciferols
Deficiency of vitamin D/calciferols
Children-rickets
Adults-osteomalacia
Where are fat soluble vitamins absorbed?
Duodenum/jejunum: all fat soluble vitamins
Ileum: vitamin D
Large intestine: microbiota produced vitamin K
Where are minerals absorbed?
Stomach and the entire intestine
Mineral involved in oxygen transport and energy metabolism
Iron
Mineral involved in wound healing and spermatogenesis
Zinc
Mineral involved in thyroid hormones
Iodine
Mineral with antioxidant properties, involved in electron transport, collagen-crosslinking, development
Copper
Mineral involved in dental health
Fluoride
Mineral with antioxidant properties and involve in thyroid hormone function
Selenium
