Bio
Metilare - Biotransformare
Bio
Metilare - Biotransformare
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- Mercurul (Hidrargir) Hg, apare in trei forme anorganice: Mercurul elementar (Hg0), Mercurul monovalent (Hg+) si Mercurul divalent (Hg2+).
| Mercurul ca forma organica: | Fenil mercuric, |
Metil mercurul |
C6H5Hg+ |
CH3Hg+ |
Cea mai toxica forma este Hg2+, de 1000 de ori mai toxica ca mercurul elementar (Hg0), este lipofil, se evapora usor.
Ioni metalici se leaga cu liganzi anionici.
- Bio Metilare - Hg (toate formele) --> Hg++ --> Metil mercurul (CH3Hg) si Dimetil mercurul (CH3HgCH3)
a) Hg2+ + Vitamina B12 (forma metil cobalamina)--> (CH3-Hg)+ (cu caracter extrem lipofil, se evapora usor)
b) (CH3-Hg)+ + Vitamina B12 (forma Metilcobalamina)- --> CH3-Hg-CH3 (Dimetil mercurul cu caracter extrem lipofil se acumuleaza in tesutul adipos al pestilor, prin consumul pestilor cu continut de metale grele se acumuleaza in tesutul adipos, cauza care blocheaza scaderea ponderala la cura de slabire.
Metil mercurul-CH3 Hg + Vitamina B12 (forma metil cobalamina) catalizator in reactie
Dimetil mercurul-CH3 Hg CH3 ajunge in atmosfera unde razele ultraviolete (UV) prin fotoliza degradeaza Mercurul (Hg) in forma elementara (Hg0)
(CH3)2Hg -----> 2 CH3 + Hg catalizator prin (bacterii)
Metil mercurul-CH3 Hg are o mare afinitate cu grupa sulfhidril (-SH).
- Chlorella alge prin terapia chelatica, formeaza cu Leurda (Allium Ursinum) si Usturoi (Allium Sativum) un complex grupa sulfhidril (-SH), care leaga toxinele si le elimina prin rinichi.
Retinopatie diabetica
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- Procesul vital de bio metilare a homocisteinei pentru regenerarea de L-Metionina
- Procesul de transulfuratie a homocisteinei, care este catalizat de enzima cistationin beta sintaza dependent de coenzima piridoxal-fosfat pentru formarea de cistationina, apoi cistationina este convertita in L-Cisteina prin enzima cistationin g-liaza deasemenea dependent de coenzima piridoxal-fosfat.
Sfecla de zahar (Beta vulgaris) |
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| TMG-Trimetilglicina |
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Formula chimica este: (CH3)3N+-CH2COO-
Formula moleculara este: C5H11NO2
Greutatea moleculara este: 117.15
- Trimetilglicina-TMG
este solubila in apa si la gust dulce
- Trimetilglicina-TMG
se mai numeste: N,N,N-Trimetilglicina,
betaina
anhidru,
betaina
glicina , betaina glicocol, oxineurina si licina.
Betaina hidroclorida HCl
Formula moleculara este: (CH3)3N(Cl)CH2COOH
Greutatea moleculara este:153.61
Betaina hidroclorida este indicat ca adjuvant digestiv.
| Ciclul metilare homocisteina |
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Denumirea chimica: 5-hidroxi-6-metil-3, 4-piridina-dimetanol, 2-metil-3-hidroxi-4,5-bis(hidroxi-metil)piridina
Formula
moleculara: C8H11NO3 - HCl
Masa moleculara: 169.17
| Vitamina B6 |
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| Vitamina B12 |
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- Vitamina
B12 forma de coenzima: Metil cobalamina, este catalizator pentru
enzima sintezei de L-Metionina,
- Vitamina
B12 forma de coenzima: Adenozil cobalamina (5-deoxiadenosilcobalamina)
este cofactor enzimei L-metilmalonil coenzyme A (metilmalonil-CoA) mutaza care
catalizeaza conversia homocisteinei in L-Metionina
Denumirea chimica: Acid pteroil-glutamic
Denumirea moleculara: C19H19N7O6
Masa moleculara: 441.4
| Acid folic |
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- Acid folic-Acid tetrahidrofolic numit si (6S)-H4folat sau (6S)-5,6,7,8-tetrahidrofolat sau [(6S)-5,6,7,8-tetrahidropteroilglutamate]
Acidul tetrahidrofolic este catalizat in 5,10-Metilen tetrahidrofolat prin enzima serina hidroxi metiltransferaza.
Radicalul CH2 = se numeste grupa metilen
- 5,10-Metilen tetrahidrofolat poate transfera un carbon rezidu la deoxiuridilic
acid formind timidilic acid,
- 5,10-Metilen tetrahydrofolat se poate transforma
in formiltetrahidrofolat care poate dona un carbon in noua sinteza de purin
nucleotid.
- Homocisteina mai poate fi metabolizata in L-Cisteina, catalizator fiind Vitamina B6 (piridoxina).
- Homocistinuria are predispozitie genetica si apare in una din aceste trei forme
Cursa de metilare (methyl trap hypothesis).
In absenta de Vitamina B12 (forma metilcobalamina) nu se poate forma conversia 5,10-metilen tetrahidrofolat in 5-Metiltetrahidrofolat prin enzima 5,10-metilen tetrahidrofolat reductaza (MTHFR), nu poate fi reconvertit in acid tetrahidrofolic (Acid folic) - Ciclul Acidului folic.
Absenta de Vitamina B12 formeaza cursa de metilare (methyl trap), cauzeaza reducerea sintezei tetrahidrofolat cu consecinta reducerii sintezei de L-Metionina si implicit reducerea conversiei in SAMe-Sulf adenozil metionina.
Sumar: Reducerea de Vitamina B12 rezulta reducerea de biosinteza nucleotidelor purinice precursor sintezei ADN (acid timidilic si purinelor), rezulta inhibarea sintezei ADN si replicarea celulara si in final se ajunge la anemiile megaloblastice
Anemiile megaloblastice induse de Vitamina B12 este cauzata de deficienta functionala celulara a Acidului folic cea ce poate fi corectat prin administrare de suplimente nutritive cu Acid folic.
Incluzind BCAA (branched-chain amino acids), aminoacizii L-Isoleucina, L-Leucina, L-Valina, ca si L-Metionina, L-Treonina, L-Tirozina, sint metabolizati de metilmalonil semi aldehida sau propionil-CoA in metilmalonil-CoA.
Enzima L-metilmalonil CoA mutaza catalizeaza metilmalonil-CoA in succinil-CoA in mitocondrie.
Succinil-CoA poate fi metabolizat in acidul tricarboxilic care produce energie si este involvat in sinteza acizilor grasi.
| Risc de arteroscleroza |
Homocisteina micromol/Litru singe
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| Risc scazut |
0.0 - 6.3
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| Risc moderat |
6.3 - 10.0
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| Risc marit |
12.0 -
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Reducerea homocisteinei prin adaugarea de suplimente nutritive de Trimetilglicina-TMG, Acid folic, Vitamina B6 si Vitamina B12 previne riscul bolilor coronariene.
SAMe-Sulf adenozil metionina este un agent principal de transmetilare la care participa acizi nucleici, fosfolipide si proteine pentru producerea de epinefrina, creatina, melatonina hormon (Anti Aging).
SAMe-Sulf adenozil metionina |
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Formula moleculara este: C15H23N6O5S
Greutatea moleculara este: 399.450000
ATP (adenozintrifosfat) + L-Metionina + H2O = Ortofosfat + Pirofosfat + S-adenozil-metionina
L-Metionina se leaga de ATP (adenozintrifosfat) pentru formarea de Sulf adenozil metionina (SAMe), aceasta reactie este catalizata de enzima metionin-adenozil transferaza
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