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Biochem Unit 2 > Ackerman Lectures 9-10 > Flashcards

Ackerman Lectures 9-10 Flashcards

1
Q

fates for glucose

A

glycolysis, PPP, glycogenesis

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2
Q

sources of glucose

A

GNG, glycogenolysis

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3
Q

GNG tissues

A

liver (1o site-when liver glycogen is depleted, provides E to brain and RBCs); kidney cortex (supp glc to kidney medulla); skeletal muscle (used here b/c still G6P (not cleaved))

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4
Q

non-carb precursors

A

lactate (RBC glycolysis), AAs (Ala, not K or L), glycerol (from TAG), propionate (fr AAs or odd-chain FAs)

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5
Q

Cori cycle

A

relationship b/w liver GNG and RBC glycolysis; anaerobic feeder pathway (GNDG, glycolysis)

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6
Q

alanine cycle

A

relationship b/w liver GNG and skel musc glycolysis; aerobic feeder pathway (GNG, ureogenesis, glycolysis)

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7
Q

GNG vs glycolysis

A

must overcome irreversible steps (PK, PFK-1, HK/GK)

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8
Q

GNG sub for hexokinase/glucokinase

A

glucose-6-phosphatase; relevant to all non-carb glucose precursors; ONLY in liver; HK isozymes have diff affin for glucose

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9
Q

GNG sub for PFK-1

A

fructose 1,6-bisphosphatase; relevant to all non-carb glucose precursors; mult allosteric effectors, hormonal ctrl (insulin, glucagon)

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10
Q

GNG sub for pyruvate kinase

A

pyruvate carboxylase (mito matrix), req CO2, biotin, ATP; then PEP carboxykinase, GTP-dep kinase w/CO2 released; relevant to all rxns w/pyruvate AND TCA metabolites; liver PK under glucagon control

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11
Q

PEP carboxykinase

A

all glucogenic precursors except glycerol

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12
Q

pyruvate carboxylase

A

only glucogenic precursors that are metabolized to pyruvate

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13
Q

HK I

A

high affin for glucose; inhib by G6P, F6P (so inhib glycolysis)

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14
Q

HK IV (GK)

A

low affin for glucose; not inhib by G6P (liver glyc can occur simult w/high [G6P]

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15
Q

PFK-1 allosteric regulators

A

+ by ADP, AMP, F2,6BP; - by ATP, citrate (lipid synth–>amplifies ATP effect)

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16
Q

FBPase-1 allosteric regulators

A
  • by AMP, F2,6BP
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17
Q

F26BP

A

ctrl’d by bifxnal enz; created by PFK-2; back to F6P by FBPase-2; cat at 2 sites in single polypep chain–homodimer

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18
Q

insulin effect on bifxnal enz

A

dephos–>activate PFK-2, inhib FBPase-2; C away from glucose (signal that glucose is high)

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19
Q

glucagon effect on bifxnal enz and PK

A

phos–>inhib PFK-2, stim FBPase-2 (signal that glucose is low, so C twd glucose); in liver PK, inactivates during GNG (ensures PEP used to make glucose, not pyr)

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20
Q

poly glucose advantages (alone and over TAG)

A

hexose monomers inc osmolarity, impede facil transport of new glc into cells; rapidly meets E needs, metab in pres/absence of O2, princ catab is glucose (fuel source for brain)

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21
Q

glycogen synthase

A

create a1-4 bonds (linear)

22
Q

branching enzyme

A

create a1-6 bonds once a glucose a1-4 chain is at least 11 units long; inc solubility, inc number of nonred ends (facil further growth of polymer, expansion of E storage capacity)

23
Q

glycogen phosphorylase

A

break a1-4 bonds (except those adj to branch points)

24
Q

debranching transglycosylase

A

transfers a1-4 link from branch to main chain (makes accessible to glyc phosphorylase)

25
Q

debranching glucosidase

A

breaks a1-6 bonds at branch points

26
Q

UDP-glucose

A

activated intermediate of glycogenesis

27
Q

glycogenin

A

primes glycogenesis pathway; self-glycosylating prot; remains at core of glycogen particle (so glycogen is proteoglycan)

28
Q

glycogenesis

A

gluco/hexokinase; phosphoglucomutase; glucose 1-P uridylyltransferase; glycogen synthase; liver must be able to make G6P cont, even in high [G6P], to feed mult paths

29
Q

glycogen synthase

A

cats elongation of glucose polymer; chem bond formation b/w C-1 glc monomer and C-4 of terminal gluc at non-red end of glycogen polymer

30
Q

glycogenesis rxn

A

G1P + UTP –> UDP-glucose + PPi; UDP-glucose + (glucose)n –> UDP + (glucose)n+1; PPi–>2Pi

31
Q

glycogenolysis

A

glycogen phosphorylase (leaves G1P), debranching enz (prod is glucose)

32
Q

glycogen phosphorylase

A

cleaves non-red end of glycogen, releases phosphorylated glucose (G1P); cannot cleave a 4-glucose unit attached at an a1-6 branch point; end prod is glucose 1-P

33
Q

transglycosylase/transferase of debranching enz

A

moves 3-glucose units to non-reducing end

34
Q

acid a-glucosidase of debranching enz

A

cleaves a1-6 bond–>release glucose (hydrolysis, no phosphate involved), leaving unbranched a1-4 polymer for further phosphorylase axn

35
Q

insulin reg of glycogen metabolism

A

activates of glycogenesis in liver and skel musc

36
Q

glucagon reg of glycogen metabolism

A

activates of glycogenolysis in liver only

37
Q

epinephrine reg of glycogen metabolism

A

activates glycogenolysis in liver and skel musc (via b-adren recep (cAMP/PKA) in both; by a-adren recep (PKC) in liver only)

38
Q

nerve stimulation/contraction

A

signals glycogenolysis

39
Q

stim glycogenolysis in liver

A

glucagon or epi (via a or b-adren recep) by activating phosphorylase kinase (PHOK)

40
Q

stim glycogenolysis in skel musc

A

epi bds to b-adren recep; epi/b-adren recep/GPCR regulation mech; Ca activates PHOK, AMP activates GPHO; GPCR–>AC–>PKA–>PK–>GP

41
Q

insulin-mediated regul of glycogenesis

A

phosphorylated glycogen synthase thru GSK3 is INACTIVE; PP1 activates GS; insulin inactivates GSK3, activates PP1 so GS active when insulin is around

42
Q

high blood glucose

A

insulin-med events; store-glycogenesis active; activate glycolysis (E, route C from CHO to fat; DHAP precursor to glycerol backbone of TAG, citrate precursor to FAs of TAG)

43
Q

low blood glucose

A

glucagone/epi-mediated events; message to liver-feed brain; message to musc-bring it on or get me out of here

44
Q

type I GSD

A

glucose-6-phosphatase deficiency

45
Q

type II GSD

A

acid a-glucosidase deficiency (debranching enz)

46
Q

type III GSD

A

transglycosylase deficiency (debranching enz)

47
Q

type IV GSD

A

branching enzyme deficiency

48
Q

type V GSD

A

musc glycogen phosphorylase deficiency (m-GPHO)

49
Q

type VI GSD

A

liver glycogen phosphorylase deficiency (l-GPHO)

50
Q

type VII GSD

A

muscle phosphofructokinase deficiency (m-PFK1) deficiency

51
Q

type IX GSD

A

phosphorylase kinase (PHOK) deficiency

52
Q

type 0 GSD

A

glycogen synthase deficiency

Biochem Unit 2 (13 decks)

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