Regular cigarette smoking influences the transsulfuration pathway
, endothelial function, and inflammation biomarkers in a sex-gender specific manner in healthy young humans.
This therefore reduces the remethylation of homocysteine to methionine and promotes the transsulfuration pathway
. This situation can however be influenced by the enzymes involved in the metabolism of homocysteine.
A previous similar study reported that SAA treatment could markedly attenuate HHcy in nondiabetic rats through enhanced production of GSH via activated transsulfuration pathway
, but whether SAA could exert similar effects on attenuating elevated Hcy level and CVD burdens in a diabetic animal with HHcy is still not clearly understood.
(4,5) Vitamin B6 acts as a cofactor in the transsulfuration pathway
, while folate and vitamin [B.sub.12] are cofactors in the remethylation period.
The second step of this pathway involves the transsulfuration pathway
, which converts homocysteine to cysteine and other products.
(25) Homocysteine is converted to cystathionine to form cysteine via transsulfuration pathway
, which is facilitated by two pyridoxal phosphate dependent enzymes, cystathionine synthase and cystathionase.
In this way, VitB6 regulates the transsulfuration pathway
which contributes to homocysteine regulation and provides cysteine synthesis and consists of sequential reactions catalyzed by CBS and CGL.
On the other hand, because plasma homocysteine was thought to be a risk factor for cardiovascular disease, vitamin [B.sub.6] is widely recognized for its importance in the inactivation of homocysteine by serving as coenzyme in the form of PLP for two degradative enzymes (cystathionine [beta]-synthase and cystathionine [gamma]-lyase) in the transsulfuration pathway
for homocysteine removal (Selhub, 1999; Miles and Kraus, 2004).
Third, the transsulfuration pathway
from homocysteine to cystathionine which is catalyzed by cystathionine beta synthase (CBS) is tightly related to the methylation pathway.
Alternatively, homocysteine can be directed to the transsulfuration pathway
and used in the synthesis of GSH (Figure 1).
Firstly, Hcy react with serine to form Ctn by catalytic action of cystathionine [beta]-synthase (CBS) through the transsulfuration pathway
. Hcy is converted into Met in the remethylation reaction.
Since, evaluations of the transsulfuration pathway
in those with an ASD diagnosis has revealed significant decreases in transsulfuration metabolites including cysteine (103)-(107), glutathione (103)-(107), and sulphate (108), impaired sulphation (150) as well as significant increases in common polymorphic variants known to modulate the methionine cycle and transsulfuration pathways
(106, 114-116), there may be a marked shift toward DHEA, and subsequent metabolites in the androgen synthesis pathway.