Glycolysis Details: The Classic Carbohydrate Catabolic Pathway G1P GP P G G HK F1,6BP F6P G6P DHAP ADP GAP 1,3 BPG. 3 PGly (3PG) PGly (2PG) DHAP

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1 ssion 9 & 10 arbohydrat atabolism Two sourcs of glucos: 1.) from blood via transportr 2.) as 1 from glycogn (animals and bactria mak glycogn, plants mak amylos) 12 Mchanism lycogn = [glucos (α1 4) glucos] with som (α1 6) branchs onrducing nd ducing nd lycogn (n units of glucos) i a Th 's ar not carbons. This is a convntion usd to dnot th following strochmistry: oxonium ion carbocation X 1 ottom attack only α lycogn (n-1 units of glucos)

2 lycolysis Dtails: Th lassic arbohydrat atabolic athway lycogn 1 a i M K D Mg 2 6 I F6 Mg 2 FK-1 D 1 mol 2 mol split F1,6 * W xpct you to know why sugar splits hr * ldolas D ldolas... Turn and D molculs upsid down D ontinus in glycolysis pathway TIM D i (2 mol) This will bcom th glycrol backbon of lipids D 2 Mol / Mol lucos 2 1,3 D M lyk ly (3) lym via 2,3 lycrat (moglobin) ly (2)

3 lycolysis Dtails (continud) 14 Two-tp Timing 2 2 pka = 30! nolas E Δ o = -62 kj / mol K M 2 mol / mol lucos 2 3 yruvat ummary not - w do not hav a lot of -- ds to b rgnratd -- nots on "shuttls"

4 gulation lycolysis is rgulatd at th thr irrvrsibl stps: 1. K 2. FK-1 3. K control is both allostric and covalnt (nzym activity altrd by covalnt modification) 4. s wll as, which is upstram of glycolysis. atur's problm: If you do glycolysis as abov, you gt (2) but you will run out of. Must rgnrat it from lcoholic frmntation omolactic frmntation spiration / Elctron Transport To rgnrat, pyruvat must b procssd by on of ths thr "ndings of glycolysis." lot of 5.07 will dal with th nds of th cll to achiv rdox balanc. 15 d to do this ( ) somhow Thr ways to achiv rdox balanc FTE glycolysis 1. lcoholic Frmntation (yasts) 2 D + 3 T 3 2 D -- bubbls in champagn -- maks brad ris 3 D 3 D 3 2 lcohol D 2 3 yruvat D = yruvat dcarboxylas ctaldhyd Ethanol Th producd gos to [prvious panl] to kp ovrall procss rdox nutral.

5 viw signal (1.) lcohol Frmntation lvant Digrssion 16 Ths ndings prvnt cll from Important (anarobic) Mtabolism of thanol in mammals running out of. Thy yasts (and yasts) convrt. glycogn fr to J. tubb nots LYLYI Thr Endings D lc D To mak glycolysis continuous, clls must find a way to rplac th 2 2 la 1. lcohol Frmntation (anarobic) 2. omolactic Frmntation (anarobic) 3. spiration: (a) D (b) T (L) (c) ET/x hos consumd hr. * spiration is coupld with "shuttls" - latr 2. omolactic Frmntation (anarobic) lactic acid bactria; animals LD in summary (abov) lactat yogurt making D - Whil frmntations ar anarobic, thy can occur in th prsnc of 2 - thy just do not us 2 - Thy ar lctronically balancd (rdox nutral) In summary to lft East sians hav an activ (vry) lcohol ldhyd D Dhydrognas, lc D, but many hav a ctyl o rlativly sluggish ldhyd D. nc thy suffr from actaldhyd toxicity ctic acid - Engry (hangovr) if thy drink too much. - lipid biosynthsis 3. spiration E shuttls will b discussd aftr w do T cycl. ath ytoplasm Malat-spartat shuttl Mitochondrion toxic lc D ctaldhyd co LD lctrons dpositd hr Thr is a similarity to path to right nimals working hard (anarobically) do lactic acid frmntation. ut th lactat from muscls can b r-built into glucos by procss of gluconognsis in th livr. Mor on this latr. ath lycrol-3-phosphat shuttl Elctrons harvstd in cytoplasm rduc oxygn in mitochondrion ET 2 2 T In th "shuttls" lctrons from ar dpositd into th mitochondrial lctron transfr chain, ET.

6 spiration: xidativ mtabolism of all mtabolic fuls (carbohyrats, fats) via ctyl o -- Mitochondrial ractions -- quir 2 (or anothr accptor) -- W can mtaboliz carbohydrats anarobically or arobically -- W can only mtaboliz lipids arobically tags: 1. D: 2. T: 3. Elctron transport and oxidativ phosphorylation Think rtrosynthtically co + Ths wnt to Introducing: Th Mitochondrion utr mmbran ytoplasm vry porous xidation of FD 2 and IM (innr mmban spac) transport co 2 + /T + + FD 2 2. T ycl - vrviw -- rcivs ctyl o from D via D (4) oxaloactat lycolysis F xidation (latr) co (2) T (Krbs) ycl (8 tps) ot: Th cycl is catalytic - 2 carbons go in; 2 carbons go out; th [intrmdiats] do not chang - thy ar th "catalysts" citrat (6) 2 2 co M F omplx V Enrgy 3 / 2 arvsting of ths 2 Innr Mmbran Matrix T, D, F oxidation, ura cycl synthsis 1 FD 2 /FD 2 1 T ~ 1 I 2 αk 2 o 12 pr 2 of co oxidizd 1. D 3 yruvat () Th hmistry * * E1 E2 E3 Toxicity of s 3 3 Lipoic acid FD o 2 roducts a.) ctyl o b.) action mchanism is strikingly similar to αkd (blow). asically, th pair of lctrons mov lft to right across D (E1 E2 E3) and rduc FD FD 2. Thn, in a rdoxchallngd last stp, FD 2 givs its lctrons to to yild. Th is oxidizd by th lctron transfr chain (latr.) itrat ynthas is strospcific. co attacks from top ( i ) fac only. Mor dtail on this latr. laisn action xaloactat () n micro-molar concntation vry prcious! o o itroyl o Unstabl! Δ o = -31 KJ/mol arbanion o 2 2 Markrs o itrat () 17 D

7 MIT pnourswar iological hmistry I Fall 2013 For information about citing ths matrials or our Trms of Us, visit:

1. PDH. The Chemistry

1. PDH. The Chemistry A Respiration: xidative metabolism of all metabolic fuels (carbohyrates, fats) via etyl oa -- Mitochondrial reactions -- Require (or another e acceptor) -- We can metabolize carbohydrates anaerobically