SHCH3-S-CH2CH2-C-MTKSACPKRATtranslocation ofbutyrylHDERgrouptoCysonβB-ketoacyl-ACPsynthase(KS)转位并进入0转酰酶下一轮循环CH3CSCH2CH2HSKSMT经过7个循环，延伸到16个C，并被ACPKRAT还原成软脂酰ACP后，硫脂酶将HDERACP上的软脂酰键转移给水分子，Butyryl-ACP反应终产物软脂酸得以释放
转位并进入 下一轮循环 经过7个循环，延伸到16个C，并被 还原成软脂酰ACP后，硫脂酶将 ACP上的软脂酰键转移给水分子， 反应终产物软脂酸得以释放。 转酰酶
HSHSKS（B-酮脂酰-ACP合酶）每延长2碳单位消耗2个NADPHKSMTKR（B-酮脂酰-ACP还原酶ACPKRATHD（B-羟脂酰-ACP脱水酶）HDERER（B-烯脂酰-ACP还原酶脂肪酸合酶B-酮脂酰-ACP还原酶OHOO福β-酮脂酰-ACP合酶-(4)还原CH-C-CH2CH3e福CH3-C-CH2-C-S(3)缩合BaNADPH+H*OHHSCH3-C-SHS>NADP+0CO2脂肪酸合酶B-烯脂酰-ACP还原酶H0β-羟脂酰-ACP脱水酶(6)再还原CH3CH2SCH3-CH2-C-CC-C1-NADPH+H*(5)脱水HHSHSNADP+H,0
(3)缩合 CO2 (4)还原 NADPH+H + NADP + H2O NADPH+H + NADP + (5)脱水 (6)再还原 KS (β-酮脂酰-ACP合酶) KR (β-酮脂酰-ACP还原酶) HD (β-羟脂酰-ACP脱水酶) ER (β-烯脂酰-ACP还原酶) β-酮脂酰-ACP合酶 β-酮脂酰-ACP还原酶 β-羟脂酰-ACP脱水酶 β-烯脂酰-ACP还原酶 脂肪酸合酶 脂肪酸合酶
SHO.CHaCHCHCHSOCHSCKSMTACPKRATKSMTtranslocation of butyrylAOEERHDKRATgrouptoCysonB-ketoacyl-ACPsynthase (KS)HDEROCH-CHa-CH2CH2C-S酰基载体蛋白S-CoAHSCoA-SHMalonyl-CoA乙酰-CoA：ACP转酰酶0KSMTCH2-CS丙二酸单酰CoA：ACP转酰酶ACPOKRATCHSβ-酮脂酰-ACP合酶HDERKSMTβ-酮脂酰-ACP还原酶ACPFatty acid synthaseKRATButyryl-ACPcomplex chargedβB-羟脂酰-ACP脱水酶HDNADP!with an acetyl andEROamalonyl group烯脂酰-ACP还原酶reduction ofNADPH+H+doublebond0①硫脂酶condensationCHSCHCHCSCO2OHSSCHSCH2CCMTKS0HSACPKRATKSMTHDEROACPKRATCH-CHCH2Etrans-2-Butenoyl-ACPERHDOHHSβ-Ketobutyryl-ACPKSMTH20ACP?NADPH + H+KRAT?dehydrationNADP+ERHDreduction ofβ-keto groupβ-Hydroxybutyryl-ACp
酰基载体蛋白 乙酰-CoA ：ACP转酰酶 丙二酸单酰CoA : ACP转酰酶 β-酮脂酰-ACP合酶 β-酮脂酰-ACP还原酶 β-羟脂酰-ACP脱水酶 烯脂酰-ACP还原酶 硫脂酶
1进位链的延伸+FQSHSHCH,CH,CH,CO-SSHCH,C-SHSCoA乙酰S-CoASH12人ACPACF1启动+NADP+?软脂酸合成的反应流程再还原NADPH0SHCH,CH-CHCO-SCH,C-SSH变位ACPACP丙二单酰-SCoA②装载脱水③H20COASHQHCH,CHCH,CO-SHOOCCH,CO-SSHCH,CO-SACPACPCH,COCH,CO-SSH还原④NADP+03)缩合ACPNADPH29CO2
29 软 脂 酸 合 成 的 反 应 流 程 CH3CO-S HOOCCH2CO-S CH3CHCH2CO-S SH OH SH SH CH3CH=CHCO-S SH O CH3C-S || SH NADP+ ⑥ NADPH 乙酰S~CoA HSCoA ① 丙二单酰-SCoA CoASH ② NADP+ NADPH ④ ⑤ H2O ③ CO2 进位 链的延伸 O CH3C-S || SH CH3COCH2CO-S SH CH3CH2CH2CO-S SH 缩合 还原 脱水 再还原 启动 装载 变位
CH,COO-CH3CH3CH3CH3COO-CH,CH2CH2CH2CCH2CCH3CH2CH2CHCH2-COO-:nCH2CH24H0C4H+CH2CH2+CH2-COO-X4eCH2O=04H*CH2+CO2Fatty acid4eC-0CO2synthaseCO2four moreadditionsCHCH2FIGURE21-4 The overall processof palmitate synthesis.ThefattyacylHSCH2chain grows by two-carbon units donated by activated malonate, withlossofCO2ateachstep.The initialacetylgroup isshadedyellow,C-1CHHSand C-2 ofmalonate are shadedpink,andthecarbon releasedas COis shaded green., After each two-carbon addition, reductions convertCthe growing chain to a saturated fatty acid of four, then six, then eightcarbons, and so on. The final product is palmitate (16:0),PalmitateThe overall process of palmitate synthesis
The overall process of palmitate synthesis