lecture 8 Flashcards
What does glucogenic mean?
can go on to make glucose
What does ketogenic mean?
can go on to make ketone bodies
which amino acids are ketogenic
leucine, lysine, ile,, thre, trp, tyr
which amino acids are glycogenic
ala,cys,gly,ser,thr,trp, asn,asp,phr,tyr,arg,his,pro
What is the pathway of L-serine synthesis
glucose–> 3pg–>s-phosphohydroxypyruvate–>3-phosphoserine–>L-serine—->glycine
Which two steps in L-serine synthesis use PLP
3-php->2-3hosphoserine and
L-serine–>glycine
What kind of reactions does PLP catalyze?
transaminase, decarboxylation, aBy elimination
why does PLP catalyze so many rxn types
it forms a covalent adduct with the substrate, stabilizing the carbanion and acting as an electron sink
what is steroelectric control?
the enzyme determine substrates and controls which bond Is broken/formed
What is the general mechanism of reactions with PLP
formation of stiffs base covalently links the amino acids the other cofactor
- destabilizes a bond to the a-carbon
-enzyme determines which bond is broken
What enzymes is biotin a cofactor for? what kind go carbon units does it Carry
fatty acid synthesis (ACC)
gluconeogenesis(pyruvate carboxylase)
- carries the most oxidized 1 c unit carboxyl group
what reactions does THF play a role in?
amino acid synthesis and degradation, purine/pyrimidine biosynthesis
What reactions does SAM play a role in?
methylates proteins, nucleic acids lipids, 2ndary metabolites.
Uses sulfuniom ion which is highly favorable
What cofactors does glycine-> serine use? What stays bound?
SHMT is bound to PLP and THF is also used, N5N10 methylene THF is formed. PLP stays covalently bound to the enzyme but THF dissociates
What is THF derived from?
folate, using enzyme dihydrofolate reductase
