Vitamins Flashcards
define apoenzyme
the large protein molecule that forms the bulk of the enzyme molecule. in isolation it may be able to bind substrate but not able to catalyse its reaction
define holoenzyme
catalytically active form of the enzyme
define substrate
the substance upon which an enzyme acts
define cofactor
non-protein molecule or metal ion that binds to the apoenzyme to form a holoenzyme.
may be bound at the active site or at a distant site on the apoenzyme
TRUE OR FALSE
the substrate may be able to bind to the apoenzyme but in the absence of the cofactor no reaction occurs
TRUUUUUE
is the intake of essential ions vital?
yes, because they act as cofactors to enzymes
what is a coenzyme?
non-protein organic compound, produced in living cells which is involved in the activation of enzymes
what substance is altered during the course of the reaction, dissociates, and then gets regenerated by another enzymatic reaction?
co-substrates
what happens to prosthetic groups during an enzymatic reaction?
they remain bound to the enzyme but still need to be regenerated
Define vitamins
it is a general term for any of several organic substances essential for normal metabolic processes and which when absent in the diet produce deficiency states as they are not produced naturally by the body
why are vitamins important?
- required for growth, reproduction, and normal body function
- lack of vitamins may result in a deficiency state
compare and contrast water soluble and lipid soluble vitamins
water soluble vitamins
- excreted via urinary route
- required daily in small amounts
- B/C
Lipid soluble vitamins
- Stored in the liver
- excessive intake causes toxicity
- ADEK
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: الي بالنص مو مصكر كامل
- Thiamine B1
- found in beans/fruit/yeast
- coenzyme: thiamine pyrophosphate (TPP)
- coenzyme to enzymes involved in carb metabolism pathway (release energy from food)
- involved in conduction of action potential
- deficiency: Beriberi
- wet beriberi: affects cardiovascular system (cardiac failure/Edema/dyspnoea)
- dry beriberi: affects peripheral nervous system (peripheral neuritis/wastage/paralysis) sever = wernicke-korsakoff
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: على الطرف من اليسار في اثنين ch3
- Riboflavin B2
- found in eggs/green vegetables/almonds
- coenzymes: flavin mononucleotide (FMN) flavin adenine dinucleotide (FAD)
- they act as prosthetic groups on flavoproteins
- involved in metabolism of macronutrients (far/carb/proteins)
- converts vitamin b6 to to its coenzyme
- acts as a H acceptor or donor (FAD→ FADH2)
- Deficiency: pellagra sine pellagra ( inflammation of mouth and lips)
- reduce iron absorption without affecting size and hemaglobin content of RBC (Normochromic normocytic anemia)
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: check the functional groups
- Niacin (left) Nicotinamide (right) B3
- found in fish/nuts/meat
- coenzymes: nicotinamide adenine dinucleotide (NAD) + Nicotinamide dinucleotide phosphate (NADP)
- NADP+ oxidizing agent
- NAD+ vital for catabolic processes ( fatty acid/glucose metabolism)
- NADPH, reducing agent, important in anabolic processes (lipid/nucleic acid synthesis)
- deficiency: pellagra (the three dees: dermatitis/dementia/diarrhea)
- toxicity state: liver damage/ skin flush
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: it looks like it’s a zigzag in one line
- Pantothenic acid B5
- found in avocado/eggs/mushroom/dairy
- milling grains greatly, reduces its content
- coenzyme: Coenzyme A
- it’s a coenzyme in fatty acid synthesis and oxidation
- involved in oxidation of pyruvate in krebs cycle
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: from the functional groups on top
- pyridoxine - pyridoxal - pyridoxamine b6
- pyridoxine (vegetable source) pyridoxal/amine (animal)
- interconvertible via phosphate group in vivo
- Coenzyme: pyridoxal-5’-phosphate
- involved in tryptophan metabolism
- deficiency is a risk for vitamin b3 deficiency
- involved in neurotransmitter production (GABA/Dopamine)
- coenzyme for 4% of enzymes, which a well over 140 reactions
- deficiency: rare CNS/Skin/ mucos disorders
- toxicity: nerve damage (pain numbness in extremities)
*
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: it’s an hour glass but it’s less than 8 and it’s not kim kardashian
- Biotin b7
- found in avocado/yeast/vegetables
- it is a coenzyme (doesnt produce one)
- required by carboxylase enzymes involved in fatty acid and glucose synthesis and amino acid break down
- deficiency: hair thinning/brittle nails/rashes/ neurological symtoms
- pergnant at risk
- eating raw eggs at risk (egg white has avidin which reduce biotin absorption)
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: idk about you but to me it looks like it is taking off ✈
- folic acid b9
- found in nuts/seeds/chickpeas/green veggies
- coenzyme: tetrahydrofolate (THF)
- important in reactions that transfer hydroxymethyl, formyl, and methyl groups in amino acid synthesis
- deficiency: megaloblastic anemia due to faulty erythrocyte multiplication and maturation
- pregnancy associated deficiency: low birth weight/ premature birth/ neural tube defects
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: it’s the only one that looks like a mess, so if it scares u then it is …..
- cobalamin b12
- found in meat/fish/milk/eggs/fermented food
- coenzyme: adenosylcobalamin/methylcobalamin
- non active dietary forms: hydroxycobalamin/cyanocobalamin
- they act as a cofactor for methionine synthase in production of THF from b9
- cofactor in molecular rearrangment reactions in CNS (metabolism of branched chain amino acids)
- deficiency: pernicious anemia/megaloblastic anemia/gi symptoms/neurological symptoms
- folic acid can reverse megaloblastic anemia
*
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: it looks like it’s called ascorbic acid
- Ascorbic acid (C)
- found in citrus fruit/guava/broccoli/brussels sprouts
- no coenzymes, it acts as a cofactor
- most powerful reducing agent in living tissue
- cofactor in hydroxylation of proline to hydroxyproline, giving triple helix of collagen its strength
- maintain metal ion in correct ionic state in enzyme active site
- cofactor in steroid synthesis/ noradrenaline production/ coversion folic acid → THF
- antioxidant (donates electrons to limit damage by free radicals)
- immune system regulation
- deficiency: scurvy (swollen gums, bruising, hemorrhage, bone frature, poor wound healing, anemia, loose teeth)
- toxicity: stomach complaints
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: it has an upside-down A on the benzene ring
- retinol (A)
- found in cod liver oil/butter/cheese/milk
- can be synthesized from carotenoids
- no coenzyme
- converted to retinal and retinoic acid in the body
- retinal converted → 11-cis-retinal by NADP+ which is an essential prosthetic group for normal function of retina
- retinal undergoes isomerisation in the presence of photon of the correct wavelength
- retinal is regenerated via RPE65 enzyme to be detected by lighy again
- important for normal embryonic development, immune function.epithelial tissue
- deficiency: night blindness, hyperkeratoic skin/ corneal damage
- toxicity: unborn child/ hypervitaminosis A (liver damage, bone pain, vision changes)
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: the one with 2 wedged lines has the number (2) in its letter name
- Ergocalciferol D2 / Cholecalciferol D3
- found in fungi / cod liver oil/ egg yolk
- not entirely obtained by diet
- d3 is formed under UV light from precursor (7-dehydrocholesterol) in the skin
- no coenzyme
- calciferol → calcifidiol in the liver
- calcifidiol → calcitriol in the kidney
- calcitriol stimulates synthesis of proteins that act as CA2+ carriers in bone
- increase intestinal absorption of ca2+ and release from bone
- maintains ca2+ and po4- at sites of new bone formation
- deficiency: rickets in children/ osteomalacia in adults
- toxicity: hypercalcemia (calcium deposit in organs/anorexia/insomnia/abnormal bone formation)
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: the long zigzag chain on top, differentiate with the double bonds
- Tocopherols/Tocorienols (E)
- found in vegetable oils
- no coenzyme
- acts as fat soluble antioxidant (protect cell membrane from oxidative damage)
- involved in smooth muscle growth and nerve maintenance
- deficiency: caused by fat malabsorption → haemolytic anemia
- toxicity: antagonize vitamin k →bleeding
Which vitamin is this?
tell me everything you know about it
VITAMIN IDENTIFICATION TIP: unlike vitamin e, the zigzag line is on the lower part of the benzene,
differentiate by length
- phytomenadione K1 long/ menaquinone K2 short
- k1 in leafy veggies (spinach/cabbage/kale)
- k2 (eggs/dairy/meat)
- intestinal flora converts phylloquinone → menaquinone
- phytomenadione k1 is a cofactor in reactions of adding carboxylic acid group onto the glutamate residues of a number of proteins to form gamma-carboxyglutamate residue
- important in formation of coagulation factors II/VII/IX/X in the liver
- involved in production of anticoagulant proteins (C/S/Z)
- warfarin drug inhibits k1 effects on coagulation
- deficiency: caused by liver damage and anticoagulant drugs → anemia/bruising/bleeding mucosa
- toxicity: no toxicity
