Tetrose
Intermediates in the Pentose Phosphate Pathway: +wl
| ← Previous revision | Revision as of 22:57, 26 April 2026 | ||
| Line 16: | Line 16: | ||
One of the metabolic pathways that a tetrose is involved in is the [[Pentose phosphate pathway|Pentose Phosphate Pathway]].{{cite journal | vauthors = Batt RD, Dickens F, Williamson DH | title = Tetrose metabolism. 2. The utilization of tetroses and tetritols by rat tissues | journal = The Biochemical Journal | volume = 77 | issue = 2| pages = 281–94 | date = November 1960 | pmid = 13687765 | pmc = 1204983 | doi = 10.1042/bj0770281 }} In the Pentose Phosphate Pathway, there is an oxidative stage and a non-oxidative stage.{{cite book | first1 = Reginald H | last1 = Garrett | first2 = Charles M | last2 = Grisham | name-list-style = vanc |title=Biochemistry | location = Boston, MA |publisher=Cengage Learning |year=2017 |isbn=978-1-305-57720-6 |pages=755–794 }} A tetrose sugar, [[Erythrose|D-erythrose]], is utilized in the non-oxidative stage, where [[ribulose 5-phosphate|D-ribulose 5-phosphate]] is generated into a 6 carbon sugar ([[fructose 6-phosphate]]) and a 3 carbon sugar ([[glyceraldehyde 3-phosphate]]). Both of these molecules can be used elsewhere in the body. |
One of the metabolic pathways that a tetrose is involved in is the [[Pentose phosphate pathway|Pentose Phosphate Pathway]].{{cite journal | vauthors = Batt RD, Dickens F, Williamson DH | title = Tetrose metabolism. 2. The utilization of tetroses and tetritols by rat tissues | journal = The Biochemical Journal | volume = 77 | issue = 2| pages = 281–94 | date = November 1960 | pmid = 13687765 | pmc = 1204983 | doi = 10.1042/bj0770281 }} In the Pentose Phosphate Pathway, there is an oxidative stage and a non-oxidative stage.{{cite book | first1 = Reginald H | last1 = Garrett | first2 = Charles M | last2 = Grisham | name-list-style = vanc |title=Biochemistry | location = Boston, MA |publisher=Cengage Learning |year=2017 |isbn=978-1-305-57720-6 |pages=755–794 }} A tetrose sugar, [[Erythrose|D-erythrose]], is utilized in the non-oxidative stage, where [[ribulose 5-phosphate|D-ribulose 5-phosphate]] is generated into a 6 carbon sugar ([[fructose 6-phosphate]]) and a 3 carbon sugar ([[glyceraldehyde 3-phosphate]]). Both of these molecules can be used elsewhere in the body. |
||
D-erythrose 4-phosphate is generated as a product of a reaction called transaldolation.{{cite journal | vauthors = Horecker BL, Smyrniotis PZ, Hiatt HH, Marks PA | title = Tetrose phosphate and the formation of sedoheptulose diphosphate | journal = The Journal of Biological Chemistry | volume = 212 | issue = 2 | pages = 827–36 | date = February 1955 | doi = 10.1016/S0021-9258(18)71021-1 | pmid = 14353884 | url = https://www.jbc.org/content/212/2/827.long | doi-access = free }} In the Pentose Phosphate Pathway, a [[transaldolase]] removes the first 3 carbon molecules of [[sedoheptulose 7-phosphate]] and places them onto a glyceraldehyde 3-phosphate. The transaldolase utilizes a [[Schiff base]] to perform a reverse [[aldol reaction]] and a forward aldol reaction in its mechanism, generating an erythrose 4-phosphate and [[fructose 6-phosphate]]. The erythrose 4-phosphate is an important intermediate in the Pentose Phosphate Pathway because it is then used in the final non-oxidative step of the pathway. |
[[D-erythrose 4-phosphate]] is generated as a product of a reaction called transaldolation.{{cite journal | vauthors = Horecker BL, Smyrniotis PZ, Hiatt HH, Marks PA | title = Tetrose phosphate and the formation of sedoheptulose diphosphate | journal = The Journal of Biological Chemistry | volume = 212 | issue = 2 | pages = 827–36 | date = February 1955 | doi = 10.1016/S0021-9258(18)71021-1 | pmid = 14353884 | url = https://www.jbc.org/content/212/2/827.long | doi-access = free }} In the Pentose Phosphate Pathway, a [[transaldolase]] removes the first 3 carbon molecules of [[sedoheptulose 7-phosphate]] and places them onto a glyceraldehyde 3-phosphate. The transaldolase utilizes a [[Schiff base]] to perform a reverse [[aldol reaction]] and a forward aldol reaction in its mechanism, generating an erythrose 4-phosphate and [[fructose 6-phosphate]]. The erythrose 4-phosphate is an important intermediate in the Pentose Phosphate Pathway because it is then used in the final non-oxidative step of the pathway. |
||
The final non-oxidative step of the pathway is a transketolase reaction. A [[transketolase]] utilizes a [[thiamine pyrophosphate]], or TPP cofactor, to break the unfavorable bond between the carbon in a carbonyl and the [[Alpha and beta carbon|alpha carbon]]. TPP attacks a [[xylulose 5-phosphate]] molecule and facilitates the cleavage of the bond between the C2 (carbonyl carbon) and the C3 (alpha carbon), where glyceraldehyde 3-phosphate is released. Then, C2 can attack erythrose 4-phosphate, which forms fructose 6-phosphate. Both of the products of this reaction can enter the [[gluconeogenesis]] pathway to regenerate [[glucose]]. |
The final non-oxidative step of the pathway is a transketolase reaction. A [[transketolase]] utilizes a [[thiamine pyrophosphate]], or TPP cofactor, to break the unfavorable bond between the carbon in a carbonyl and the [[Alpha and beta carbon|alpha carbon]]. TPP attacks a [[xylulose 5-phosphate]] molecule and facilitates the cleavage of the bond between the C2 (carbonyl carbon) and the C3 (alpha carbon), where glyceraldehyde 3-phosphate is released. Then, C2 can attack erythrose 4-phosphate, which forms fructose 6-phosphate. Both of the products of this reaction can enter the [[gluconeogenesis]] pathway to regenerate [[glucose]]. |
||
