Dr. T. Akhtar's Flashcards
Primary metabolism
for growth and development, ex fatty acids, amino acids, nucleic acids
secondary metabolism
not directly involed in growth and development ex. isoprenoids, alkaloids, phenolics
name 2 alkoloids used in health
serotonin- makes us happy and helps regulate the GI tract
vinblastine- treats cander
name an alkaloid used in ecology
male butterflieds feed on heliotropiun indicum that produce pyrrolizidine alkaloids. Protexts the butterfly from certain spiders
where are alkaloids found in agriculture>
crooked calf disease–> accumulation of toxis alkaloid species in lupin seeds. (silvery lupine)
how are the alkaloids used in plant defence?
toxic or function as deterrents.
where does the word Alkaloid originate
Arabic work ‘al-qui’ plant from sodium carbonate
what are glucosinolates?
mustard oils, they are sulfur and nitrogen containing plant secondary metabolites.
order brassicales->brassica crops
what are the 3 main classes of glucosinolates?
- Alphatic (Ala, Leu, Ile, Val, Met)
- Aromatic (Phe, Tyr)
- Idololic (Trp)
what are the 3 phases of glucosinolates synthasis?
- elongation by inserting methylene groups to side chain
- core structure by matabolically reconfiguring the amino acid moeity,
- secondary modifications:
why do plants undergo glucosinolate degradation
upon plant damage glucosinolate are degraded to a variety of hydrolysis products that are responsible for all the biological acitvities of this compound class.
explain the steps in glucosinolate degradation
- thioglucoside linkage–myrosinase—> glucose + *agylcone
- algycone–> isothiocyanates/ epithionitriles/ thiocyananates
- ESP dictates nature of degradative products
what are bioactive prodcuts
- isothiocyanate,
- nitrile
- epithionitrile
- oxazollidine-2-thione
what is the glucosinolate-myrosinase system? and do plants avoid the toxicity?
chemical herbivory defence system
plant protects its self by seperating glucosinolates and myrosinase, so that the thioglucoside linkage on glucosionalte cannot convert to agyclone.
what are the degradation products of the glucosinolate-myrosinase system?
- myrosinase and glucocosinolate
what can protect an animal from the toxic effects of glucosionlate?
an ezyme called glucosinolate sulfatse can desulfates the glucosinolates, to no longer be able to be hydrolyzed
what way could you engineer an insert to be resistant to toxic effects of glucosinolates?
- design a desulferizing enzyme
2. a method to permenantly seperate the glucosinolate from the myrosinase
what synthesizeds an isoprenoid?
synthesized from IPP and its isomer DMAPP
what are the two pathways of IPP/DMAPP syntehsis?
MVA (mevalonic acid pathways) and MEP (methylerythritol phosphate pathway)
what are the two IDI isomers in plants and where are they located?
IDI1- plastid and cytosol
IDI2- mitochondria
what is prenultransferase?
its a group of enzymes that catalyze in a “heat-2-toe” condensation of IPP and DMAPP. Additional rounds give longer chains. final chain length determined by specifity of the phenyltransferases.
what are the two types of phenyltransferases
- TPTs add the C5 IPP in the trans configuration–>GPP
2. CPTs add IPP in cis configuration -> NPP.
what are the names for the prenyltransferases that are C10, C15, C20 ,
C20L diterpenes
what is a trichonme?
specialized leaf structure where terpenes are syntehsized, small epidermal appendages on surface of leaves, stems, fruits and flowers. ~20% of leaf dry weight
what analyzes terpenes?
GC-MS, due to high volatility.
what are the 2 terpenes are found in tomatoes
b-phellandrene (monoterpene)
B-caryophyllen (sesquiterpne)
which type has a greater variety?
sesquiterpenes becuase of the additional 5’C to react with intermediates. 7:1.
what is the function of isoprenoids?
cholesterol terpenes sterols carotenoids. ETC
what is HMG-CoA reductase
enzyme that catalzes
HMG-CoA—–> MVA
regulated by:
feedback, transcription, translation, phosphoryltation and degradation.
what is prenyltransferase
catalyzes the head to tail condensation of IPP onto DMAPP to produce GPPS, FPPS, GGPS
what are examples of cis-prenyltransferases
NPPS, Z,Z-FPPS
what are examples of trans-prenyltransferases
GPPS, FPPS, GGPS
how many classes of (terpene synthases) TPS are there?
- Type 1, and Type 2. most plants fall into type 1.
where are terpenes synthesize?D
in Trichomes
what are the 3 kinds of monoterpenes?
- acyclic,
- monocyclic
- bicyclic
give 4 examples of acyclic monoterpenes
citral
geraniol
linalool
mycrene
give 4 examples of monocyclic monoterpenes
limonene
menthol
thymol
p-cymeme
give 4 examples of bicyclic monoterpnes
eucalyoptol
pienne
carene
thujene
give 3 examples of sesquiterpnes
zingiberene
cadienne
pathoulol
what are long chained isoprenoids?
30C =condensation of 2x FPP—squalene synthase–>squalene
40C= condensation of 2xGGPP—phetonene synthase—>phetone
what are carotenoids?
tetraterpenes formed by 2xGGPP molecules. may require 3 more enzymes to make lycopene.
GOLD rice project we cant make enough
whar are substrates for the DXP-synthase enzyme?
glyceraldehyde-3-phosphase (G3P)
pyruvate.
what is a vitamin?
organic compounds that must be ingested since the body cannot synthesize them
what is thiamine?
B1- required for catabolism of sugars and amino acids (in plants). used in animals for acetylcholine and G ABA synthesis. deficiency causes beriberi in humans
what does Thi4 (Thi1) do>
Thi4 converts NAD+ +glucine +S—–> andenylated thiazole carboxylate
describe thiamine biosynthesis in prokaryotes
5 enzymes +cysteine + glycine or tyr + DXP
describe thiamine biosyntesis in eukaryotes
1 enzyme + NAD + glycine + 5c sugar+ S-
explain the coupling of thiazole and pyrimidine moieties in prokaryotes
HMP-P is phosphorylated by ThiD and condensated with thiazole phosphate carboxylate by ThiE, producing ThMP
explain the coupling of thiazole and pyrimidine moieties in eukaryotes
HMP-P and phosphorylated and concendese by a bifunctional enzyme THI1/THI3 to form ThMP
how is thiamine acitvated?
ThMP is phosphorylated to ThDP by ThiL (in bacteria) and TPK (in plants)
how is thiamine regulated?
THI-box Riboswitch mechanism of ThiC and THI1
what reactions require thiamine to function?
Pyruvate dehydrogenase complex.
what is folate
a B vitamin and a tripartile molecule
what drug inhibits folate synthesis?
Sulfanilamide-
What are folate mediated C1 reactions?
donated C1 subunits:
- histidine breakdown
- interconversion of serine and glycine
- production of glycine from dimethylglycine
- glycine oxidation
- N-10-formyl-THF
how can THF isoforms be formed?
through additions to the N5, and N1 positions on THF.
name 5 folate interconversions
- 5-methyl-THF
- 10-formyl-THF: purine synthesis ->AMP/GMP
- 5,10-methenyl- THF
- 5,10-methylene-THF
- 5-formyl-THF
What is the MTHFR deficiency
MTHFR polymorphism- causes a biuld up in homocysteine, low methionine levels.
what is riboflavin
vitamine G, almonds and leafy vegetables. composed of ribose and flavin (purine) moeities.
what are FAD and FMN
these are essential redox cofactor
how is riboflavin converted to FAD and FMN?
its phosphorylated by RFK to produce FMN. FMN is then coupled with ATP-derived AMP moeity to FADS to produce FAD.
what are the 3 redox states of riboflavin?
- fully oxidized quinone
- one-electron semiquinone
- fully reduced hydrioquinone
what bitter acids are present in hops?
prenyalted acylphoroglucinols, derived from branched chain amino acids (Leu, Val Ile) `
explain the photo-oxidation of isohumulone
upon irradiation with visble light, concentration of MBT increase Isohumulone and riboflavin are pivotal for this reaction.
how is riboflavin a photosensitor?
it exhibits an absopriton spectra @ 375/445 nm and upon absorption it can become activated and can create ROS
what part of riboflavin makes it yellow?
the flavin moeities, the fully oxidized form of riboflavin, quinone.
what compound is required for both folate and riboflavin synthesis?
GTP- Guanosine-5’-triphosphate
what kind of chemical reactions does riboflavin participate in?
Redox reactions
what is a phenolic?
an aromatic hydrocarbon ring with an additional hydroxyl group
name 3 types of phenolics
phenylpropanoids- +C3 sidechain
Benzoic acid derivatives (C6-C1)
coumarins (C6-C3)
what are the phenolic precursors?
- Aromatic Amino Acids: Phe and Tyr (tryptophan)
why is chorismate an imporant branch point?
one branch leads to the formation of Phe and Tyrosine and the other results in tryptophan formation.
it makes AAA, folate, Phe, Trp
what is the enzyme that commits chorismate to Phe and Tyrosine? and what regulates it?
chorismate mutase, and it controlled thoguh Phe, and Tyr feedback.
what does benzenoid acid derivatives (benzoids do)?
they attract pollinators. they come from Phe.
Phe—-PAL—–> transcinnamic acid + NH3
where is beta-oxidation pathway and non-beta-oxidation pathways analogous to?
beta-oxidation ->peroxisomes
non-beta->cytosol
what are the intermediates of oxidative and non-oxidative pathways
oxi-> BA-CoA
non-oxi->BAld
what does AAT conver?
Phe to PhPyr
what does PAAS convert?
Phe- to PhA
what volatile compounds derived directly from phe
Gc, various volatile compounds emitted by those flowers.
what is the core phenylpropanoid pathway
pathway convert phenylalanime (and tyrsosine) to the simple phenylpropanoids trans-cinnamic acid, p-coumaric acid, and p-coumaroyl-CoA.
what are examples of simple phenolics
Benzoic acid derivatives
phenylpropanois
coumarins
what are examples of more complex phenolics
flavonoids
lignin
stilbenes
what are coumarins?
defense role in plants
ingesting clover massive internal bleeding- help strokes
what are HCAs
have C6-C3 strucutre
ex. cafferic acid
ferulic acid
sinapic acid
where is lignin syntehsized? and what are the resulting monolignols?
cytosol
the following 3 alcohols
G-unit, H unit, S unit.
what ligning is derived from the following monolginol units G, H, S?
G- guiaiacyl lignin
H->p-hydroxphenyl lignin
S-> syringyl lignin
how is lignin ploymerized?
cytosol—>cell wall via glycosides–>oxidized—>lignin polymer.
use these enzymes: peroxidase, oxidases and laccases.
what are the precursors to flavanoids?
p-coumaroyl CoA and Malonyl CoA.
when catalyzed by CHS they make chalone. all 3 together make STS.
Chalone is a precurosr for what?
flavonols
isoflavanoes
flavanones
anthocyanidins
Flavonoids exist primarily as?
glycosides or actylated derivatives
40% of the carbon in the atmosphere exist within which class of plant phenolics?
phenylpropanoids
how many linear chains are typically found in a microfirbil chain in cellulose wall?
30-36
what enzyme is responsible for cellulose synthesis, and where is it found in the cell?
outer face of PM, and by CeSA.
whats another name for pectin and what ion holds it together
Galacturonans, held together by Ca 2+
what are the two classes of lipids,
- Fatty Acids (saturated and unsaturted)
2. Glycerolipids (triacyglycerols, phospholipids, galactolipids, sulfolipids)
name the phospholipid associated to their fatty chains?
- H- dicylglycerol
- R3-Triacylglycerol
- phosphate- phospholipid
- galactose- galactolipid
how does a double bond affect a hydrophobic tail?
spacious, lower melting point, and increase fluididity
What are the 5 plant glycerolipid
- TAGs
- phospholipids
- galactolipids
- sulfolipids
- sphingolipids
what are TAGs-
neutral lipids,
fats and oils are mixtures of tags
what are phospholipids
derived from esterification of poiar head group to the phosphoryl group
amphipathic containing both hydrophobic fatty acids and a hydrophilic head group.
formed in plastid and ER
what are galactolipids
found in PM and are synthesized from phosphatidic acid.
has a galactosyl or sulfoquinovosyl group.
what are sphingolipids
concentrated in PM,
play a signal transduction and cell recognition and hos-pathogen interactions
what are phosphatidylinositol PI
structural lipid and presurosr for secondary mesenger production
secerral derivatives known as PtdIns– converts into IP3 and DAG.
what does IP3 do?
specifically inducdes Ca2+ release from intracellular stores
What does DAG do?
modulates activity of protein Kinase C.
where does the biosynthesis of fatty acids occur
in plastids,
what precursor is initially used in fatty acid biosynthesis?
Acetyl-CoA
what converts pyruvate into acetyl-CoA?
PDC and there is additional product of NADH
name the two coenzymes A breaks into, and from what are they derived?
CoA, CoASH,
derived from vit B5, ATP, and cysteine
what does ACCase do?
activates acetyl-CoA to malonyl CoA. its 2 step reaction requires 3 conserved structural domains and 4 non-catalytic biotin containing component.
what does malonyl-CoA do?
its required outside the plastic where it serves as a substrate for a variety of enzymes.
what is HOM-ACCase
its found in animals, fungi. its also cytosolic, and is a single functional polypeptide with 3 functional domains
what HET-ACCase
its found in plastid, and is present in bacteria, and plants
what is an emzyme used in ACCase reaction?
BC and it is carried and transported BCCP. and further transported via alpha-CT and Beta-CT.
what is fatty acid synthase (FAS)
the types of enzymes that activate in fatty acids biosynthesis except ACCase.
what are the two type of FAS
type 1- catalyzes several different reactions, common to mammals and fungi. its characterized by a large subunits.
type 2- common in most bacteria and plants.
the assembly of fatty acids involves a central cofactor. what is it?
ACP
