Flashcards in Water soluble vitamins Deck (30):
a group of organic nutrients, required in small quantities for a variety of biochemical functions. They cannot be synthesized by the body.
Non- B- Complex vitamins
Ascorbic Acid (vitamin C)
-the transfer of a pyrophosphate group from ATP to thiamine.
-particularly important in...
-as a coenzyme: of transketolase and in oxidative decarboxylation of α -keto acids reactions.
-tissues of the nervous system.
-Beriberi, dry skin (adult), vomiting (kids), depression, mental confusion, Wernicke- Korsakoff syndrome
-main dietary sources...
-flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).
-milk and dairy products
-active forms are capable of...
-reversibly accepting two hydrogen atoms and are bound tightly to flavoenzymes that catalyze the oxidation or reduction of a substrate.
-not associated with a major disease, dermatitis, glossitis.
Niacin or Nicotinic acid
-different than the others because...
-It is not strictly a vitamin since it can be synthesized in the body from the essential AA tryptophan.
-nicotinamide adenine dinucleotide (NAD+) and NADP+.
Niacin or Nicotinic acid
-grains and cereal, milk, lean meat
Is a disease involving the skin, gastrointestinal tract and CNS.
NAD and NADP
-in which vitamin
-coenzymes in oxidation- reduction reactions
It is a coenzyme that serves as a carrier of activated O2 and it is present in carboxylation reactions:
-Methylcrotonual - CoA
-widely distributed in food, intestinal bacteria
-raw egg prevents its absorption from the intestine, dermatitis, glossitis, loss of appetite.
It is covalently bound to amino groups of lysine residues in biotin-dependent enzymes
Pantothenic Acid (B5)
-coenzyme A (CoA) and acyl carrier protein (ACP).
-in the transfer of acyl groups
-eggs, liver, yeast
-key role in...
-one- carbon metabolism
-fortified grains, liver, green vegetables
-megaloblastic anemia, neural tube defects in fetus, affects cells that are dividing rapidly.
-how does the one- carbon metabolism occurs
1. Tetrahydrofolate receives one-carbon fragments from donors (serine, glycine, and histidine)
2. Transfers them to intermediates in the synthesis of amino acids, purines, thymidine monophosphate (TMP).
-required in humans for...
-two essential enzymatic reaction
-unusual fatty acids accumulate become incorporated into cells membranes, including those of the nervous system. Pernicious anemia.
Two essential enzymatic reaction in which vitamin B12 is required
1. Remethylation of homocysteine to methionine
2.Isomerization of methylmalonyl coenzyme A
-synthesized only by microorganisms, not present in plants, liver, whole milk, eggs
Vitamin B12 absorption
-absorbed bound to intrinsic factor (= a small glycoprotein secreted by the parietal cells of the gastric mucosa).
(look in my notes for more details)
Deficiency of vitamin B12 happens more often due to...
failure to absorb the vitamin from the intestine
-collective term for...
-Reaction involving AA..
-pyridoxine, pyridoxal, pyridoxamine.
-deamination, decarboxylation, condensation
Cofactor of glycogen phosphorylase
steroid hormone action - removes the hormone-receptor complex from DNA binding, terminating the action of the hormones
-dietary source, many foods.
-isoniazid can induce it, deficiencies are rare (alcoholics, newborns on formula, oral contraceptives)
Pyridoxine is the only water- soluble vitamin with...
significant toxicity - neurologic symptoms.
-as a reducing agent in several different reactions and as a coenzyme in hydroxylation reactions
-citrus fruits, lettuce, tomato, dark green vegetables
-easily destroyed by...
-heat and oxygen
-Scurvy due to deficiency in the hydroxylation of collagen, spongy gums, loose teeth, swollen joints.