Siklus asam sitrat: Perbedaan antara revisi
Konten dihapus Konten ditambahkan
k →Sekilas proses: wk |
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Baris 37:
* Energi yang dihasilkan dari reaksi oksidasi dikirimkan dalam bentuk [[elektron]] menuju [[Nikotinamida adenina dinukleotida|NAD<sup>+</sup>]], membentuk NADH. Untuk setiap gugus asetil, akan terjadi tiga molekul NADH.
* Elektron juga dikirimkan ke penerima [[flavin adenina dinukleotida|FAD<sup>2+</sup>]], membentuk FADH<sub>2</sub>.
{| class="wikitable"
!
![[Substrat]]
!Produk
![[Enzim]]
!Reaksi
!Keterangan
|-
|1
|[[Asam oksaloasetat|Oksaloasetat]] +<br />[[Asetil-KoA]]
|[[Asam sitrat|Sitrat]] +<br />[[Koenzim A|CoA-SH]]
|[[Sitrat sintase]]
|[[Kondensasi aldol]]
|rate limiting stage (irreversible), <br />extends the 4C oxaloacetate to a 6C molecule
|-
|2
|[[Asam sitrat]]
|''[[Cis–trans isomerism|cis]]''-[[Aconitic acid|Aconitate]] +<br />H<sub>2</sub>O
|rowspan=2|[[Asonitase]]
| [[Reaksi dehidrasi|Dehidrasi]]
|rowspan=2|reversible isomerisation
|-
|3
|[[Asam asonitat|''cis''-Asonitat]] +<br />H<sub>2</sub>O
|[[Asam isositrat|Isositrat]]
|[[Reaksi hidrasi|Hidrasi]]
|-
|4
|[[Asam isositrat]] +<br />[[Nicotinamida adenina dinukleotida|NAD]]<sup>+</sup>
|[[Asam oksalosuksinat|Oxalosuksinat]] +<br />[[Nicotinamida adenina dinukleotida|NADH + H <sup>+</sup>]]
|rowspan=2|[[Isositrat dehidrogenase]]
|[[Oksidasi]]
|generates [[NADH]] (equivalent of 2.5 ATP)
|-
|5
|[[Asam oksalosuksinat]]
|[[Asam ketoglutarat-alfa|Ketoglutarat-α]] +<br />CO<sub>2</sub>
|[[Dekarboksilasi]]
|irreversible stage, <br /> generates a 5C molecule
|-
|6
|[[Asam ketoglutarat-alfa|Ketoglutarat-α]] +<br />NAD<sup>+</sup> +<br />CoA-SH
|[[Suksinil-KoA]] + <br />NADH + H<sup>+</sup> + <br />CO<sub>2</sub>
|[[Ketoglutarat-alfa dehidrogenase|Ketoglutarat-α dehidrogenase]]
|Oksidatif<br />[[Dekarboksilasi]]
|irreversible stage, <br /> generates NADH (equivalent of 2.5 ATP), <br /> regenerates the 4C chain (CoA excluded)
|-
|7
|[[Suksinil-KoA]] + <br />[[Guanosina difosfat|GDP]] + [[Fosfat inorganik|P<sub>i</sub>]]
|[[Asam suksinat|Suksinat]] +<br />CoA-SH +<br/>[[Guanosina trifosfat|GTP]]
|[[Suksinil koenzim-A sintetase|Suksinil-KoA sintetase]]
|[[substrate-level phosphorylation]]
|or [[adenosina difosfat|ADP]]→[[adenosina trifosfat|ATP]] instead of GDP→GTP,<ref name=[[Stryer]]>{{cite book |last= Berg |first=JM |coauthors= JL Tymoczko, L Stryer |title= Biochemistry - 5th Edition |pages =476|publisher= WH Freeman and Company |year=2002 |isbn= 0-7167-4684-0}}</ref><br />generates 1 ATP or equivalent
|-
|8
|[[Asam suksinat]] + <br />[[ubiquinone]] (Q)
|[[Asam fumarat|Fumarat]] + <br />ubiquinol (QH<sub>2</sub>)
|[[Suksinat dehidrogenase]]
|Oksidasi
|uses [[FAD]] as a [[prosthetic group]] (FAD→FADH<sub>2</sub> in the first step of the reaction) in the enzyme,<ref name=[[Stryer]]>Berg ''et al.'' (2002), page 501</ref><br/>generates the equivalent of 1.5 ATP
|-
|9
|[[Asam Fumarat]] + <br />H<sub>2</sub>O
|''L''-[[Asam malat|Malat]]
|[[Fumarase]]
|H<sub>2</sub>O addition<br />(''hydration'')
|
|-
|10
|[[Asam malat|''L''-Malat]] + <br />NAD<sup>+</sup>
|[[Asam Oksaloasetat]] + <br />NADH + H<sup>+</sup>
|[[Malat dehidrogenase]]
|Oksidasi
|generates [[NADH]] (equivalent of 2.5 ATP)
|}
== Lihat pula ==
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