Chuyển hóa lipid

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Lipidng vtThc vt

D tr nng lng

Ch yu d tr carbon

soybean

sunflower

cotton

peanut

avocado

olive

Qu trnh sinh tng hp 2 loi glycerolipids: - Triacylglycerol- Glycerolipids phn cc

S hp tc ca th ht v li ni cht.

Qu trnh t ht ging ny mm c c nnglng chuyn ha t qu trnh oxy ha cht bo

QU TRNH TRAO I CHT LIPIDCht bo v du lu tr mt lng ln nng lng Triacylglycerol lu tr trong Oleosomes Cc Glycerolipids l cu trc lipid ch yu trong mng Sinh tng hp acid bo Glycerolipids c tng hp trong plastid v ER Lipid mng t bo Lipid d tr chuyn thnh Carbohydrates ht ny mm Tng quan: Lipid ti ng sucrose

Du v m d tr mt lng ln nng lng Cc loi m v du u thuc nhm cht bo. Cht bo i din cho hnh thc carbonthu gn hn carbohydrates.

Qu trnh oxy ha hon ton:1g m hoc du (~ 9.3 kcal)

1g tinh bt (~ 3,8 kcal)

Qu trnh sinh tng hp cung cp nng lng ln tng ng vi nng lng chuyn ha.

terpenoid waxe Lm gim s mt nc

carotenoid Tham gia vo qu trnh quang hp

sterol C nhiu trong mng t bo thc vt

Triacylglycerol lu tr trong OleosomesDu v m tn ti ch yu di dng triacylglycerol (acyl m ch n phn acid bo), hoc cht bo trung tnh

Du th l cht lng nhit phng. M, trong chim mt t l cao trong cc axit bo bo ha, rn nhit phng.

Cc axit bo trong thc vt:Mch axit cacboxylic dng thng

S nguyn t carbon chn, thng l 16-18C

Triacylglycerol c d tr trong TBCca 1 trong 2 l mm hoc cc tb ni nh trong bo quan c bit n nh (spherosomes hay th du)

Lp n phospholipid (mt halfbilayer) bao quanh th du. n nh bi s hin din

ca nhng protein xcnh, gi l oleosins.Cu trc mng t bo c o ca oleosome l kt qu t m hnh ca sinh tng hp triacylglycerol.

Glycerolipid phn cc l cu trc lipid ch yu trong mng

Phn k nc: 16C-18C ester ha v tr 1 v 2 ca glycerol. u phn cc gn v tr 3

C 2 loi u cc glycerolipids:Glyceroglycolipids Glycerophospholipids

Mng t bo thc vt c thm cu trc lipid. Bao gm c sphingolipids v sterol

Mng lc lp chim 70% ca cc mng lipid trong cc

m quang hp, c glyceroglycolipids chim t l cao. Cnli cha glycerophospholipids.

Trong cc m khng quang hp phospholipids l chyu ca mng glycerolipids.

Sinh tng hp acid bo bao gm cc chu trnh b sung 2C thc vt, acid bo c tng hp ring trong lp th.

ng vt, acid bo c tng hp ch yu bo tng.

Phc hp enzyme tng hp acid bo

Cho php phn ng xy ra hiu qu hn l cc enzyme tch ri nhau

S tng hp malonyl-CoA t acetyl-CoA v CO2

Malonyl-CoA phn ng vi ACP to ra malonyl-ACP

S iu chnh cht ch Acetyl-CoA carboxylase dng nh kim sot c ton b t l ca s tng hp acid bo

Nhm acetate t acetyl-CoA chuyn n cysteine c trng ca enzyme ngng t (3-ketoacyl-ACP synthase).Sau kt hp vi malonyl-ACP thnh acetoacetyl-ACP. Nhm keto carbon 3 c loi b bi cc tc ng ca ba loi enzyme to thnh butyryl-ACP. Butyryl-ACP v malonyl-ACP khc sau tr thnh cc c cht mi cho enzyme ngng t, kt qu l b sung thm 2carbon vo chui, v vng tip tc cho n khi 16 hoc 18 nguyn t cacbon c thm vo. Hu ht cc phn t c ko di n 18:0 ACP c chuyn i sang 18:1 ACP bi mt enzyme desaturase. S lp li ny to ra 16:0 ACP v 18:1-ACP l cc sn phm ch yu ca s tng hp acid bo th ht.

Butyryl-ACP v malonyl-ACP khc sau tr thnh cc c cht mi cho enzyme ngng t, kt qu l b sung thm 2-carbon vo chui, v vng tip tc cho n khi 16 hoc 18 nguyn t cacbon c thm vo.

Nhm acetate t acetyl-CoA Sau kt hp vi malonylchuyn n cysteine c trng ACP thnh acetoacetylca enzyme ngng t (3ACP ketoacyl-ACP synthase).

Nhm keto carbon 3 c loi b bi cc tc ng ca ba loi enzyme to thnh butyryl-ACP.

Hu ht cc phn t c ko di n 18:0 ACP c

chuyn i sang 18:1 ACP bi mt enzyme desaturase.S lp li ny to ra 16:0ACP v18:1ACP l cc sn phm

ch yu ca s tng hp acid bo th ht.

Glycerolipids c tng hp trong th ht v ERHai phn ng acyl ha chuyn cc axit bo t acyl-ACP hoc Cc axit glycerol-3-phosphate ht tip theo acyl-CoA tibo tng hp trong thto thnh axid c s phosphatidicdng to glycerolipids ca mng v

oleosomes.Tc ng ca mt phosphatase c hiu l sn xut diacylglycerol (DAG) t axit phosphatidic. Acid phosphatidic cng c th c chuyn i trc tip thnh phosphatidylinositol hoc phosphatidylglycerol. DAG th gy ra s tng ln ca phosphatidylethanolamine hoc phosphatidylcholine

Hai con ng tng hp Glycerolipid: con ng prokaryotic (lc lp) v con ng eukaryotic (ER) Con ng prokaryotic s dng 16:0 v 18:1-ACP sn phm tng hp acid bo ca lc lp tng hp acid phosphatidic v cc dn xut ca n. Ngoi ra, cc axit bo c th c chuyn sang cc t bo cht nh l ester CoA.

Con ng eukaryotic s dng mt thit lp ring bit ca acyltransferases trong ER kt hp cc acid bo thnh acid phosphatidic v cc dn xut ca n.

Trong mt s thc vt bc cao (Arabidopsis v bina) 2con ng c vai tr gn nh nhau tng hp lipid lc lp. Tuy nhin, nhiu cy ht kn khc, phosphatidylglycerol

l sn phm duy nht ca con ng prokaryotic, v cclipid lc lp cn li c tng hp hon ton bng con

ng eukaryotic.

Tng hp triacylglycerol trong ht c du thng l ging vi glycerolipids. Cc enzyme quan trng trong qu trnh trao i cht ca ht c du l acyl-CoA: DAG acyltransferase v PC: DAG acyltransferase, l cht xc tc tng hp triacylglycerol. Cc phn t triacylglycerol tch t trong cu trc di mc t bo chuyn bit oleosomes- m t chng c th

c huy ng trong qu trnh ny mm v chuyn ithnh ng.

mng t bo

Thc vt, ng vt v vi khun s dng lipidmng nh tin thn i vi hp cht c s dng cho tn hiu ni bo hoc tm xa.Jasmonate bt ngun t acid linolenicBo v TV khi cn

Phosphatidylinositol

4,5-bisphosphate(PIP2)T gii phng Ca2+ vo t bo cht

Lipid

trng, nm bnh

V d:

iu ha s pht trin ca TV (bao phn, phn hoa)

iu chnh chu trnh tb, k c t bo kh khu

Lipid d tr chuyn thnh Carbohydrates ht ny mm Sau

khi ny mm, ht cha du chuyn ha triacylglycerol

c d tr bng cch chuyn i cht bo to ng sucrose.

Thc vt khng c kh nng vn chuyn cht bo tcc ni nh chuyn n m ca cy con ny mm, do chng phi chuyn i cht bo c d tr nh mt hnh thc di ng ca sucrose ,carbon ni chung.