Week 5 Other signficant classes of compounds Flashcards
what are polyketides
they are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone and methylene groups.
what are fatty acids
they are carboxylic acids with an aliphatic chain, whihc are either saturated or unsaturated. Most naturally occuring fatty acids have unbranced chain of an even number of carbon atoms, from 4 to 28
type 1 modular polyketide synthase
are enzyme assembly lines for the synthesis of chemically diverse polyketide natural products
In the polypeptide chain the alternate carbon atoms come from the methyl and carbonyl groups of the acetate building block.
what do many plant oils and animal fats contian
the contain long chain monocarboxylic acids known as fatty acids
in the fatty acids the carbonyl group of the acetate unit is reduced during the course of the chain assembly process
what are the process to get to unsaturated fatty acids
dehydrogenation and oxidative processes may subsequently give rise to unsaturated fatty acids. If some carbonyl groups aren’t removed then Aldo’s-type rearrangements can occur leading to flavonoids.
how are fatty acids found in fat
they are found as free acids, and more often as esters with alcohols such as glycerol and cholesterol
common fatty acids have an even number of carbons typically C12-C20. linked in a straight chain with up to four double bonds
examples of fatty acids and their origin
myristic acid C14 is found in nutmeg seeds and palmitic acid C16 is found almost all plant oils
what are the two essential c18 fatty acids
alpha-linolenic (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid) these cant be synthesised in the human body and must be obtained from food.
Omega 6 and omega 3 poly-unsaturated fatty acids are…
precusors to potent lipid mediator signaling molecules (eicosanoids)
PUFAs are enzymatically converted to the bioative C20 and C22 homologues through a process of elongation and desaturation
what is the difference betwen fatty acids from omega 6 and omega 3
eicosanoids derived from omega 6 are pro-inflammatory and for omega 3 are anti-inflammatory
what are eicosanoids
are short lived, regulatory lipidsthat meidate regulation of blood pressure. inflammatory and immune responses.
glucosinolates
sulphur-containing glycosides found in abundance in vegetables of family Brassicaceae.
Have a Beta-thiogluccose , variable side chain from an amino acid. Suffocated oxide moiety
they are not toxic, they are converted to isothiocyanate via the action of V-thioglucosidase enzymes known as myrosinases)
Tyrosinase and glucosinolates are kept separate to prevent the formation of toxic compounds in plants
the breakdown products of glucosinolates
are electrophilic and modify both thiols and amines
amino acids are precursors for the biosynthesis of glucosinolates
biosynthesis of glucosinolates
al
in
aliphatic glucosinolates derive from methionine
indole glucosinolates from tryptophan and aromatic glucosinolates from phenylalanine
Thiosulphinates
allicin is a sulphur containing natural compound responsible for the typical smell and taste of freshly cut or crushed garlic
allicin is a thiosulfinate and isproduced after damage to plant tissue by enzymatic reaction.
