[0:00]Hello friends, today's topic is about one carbon metabolism. So this one carbon group like CH, CH2, CH3, they are also important in various reaction in our body.
[0:10]But it is considered as a part of the protein metabolism because this one carbon metabolism is related with the amino acid metabolism also.
[0:20]So you have to remember this one carbon metabolism, so exactly how it is occurring in our body, that we will look in this video.
[0:24]So, one carbon compound play a key role in donating carbon atom for synthesis of different compounds.
[0:29]So, CH group, CH2 group that will be donated with the help of this one carbon group for the synthesis of different compound.
[0:35]So, this different one carbon group of our body like called as like one carbon pool are first one that is methenyl group, that is CH means carbon have a four valency.
[0:46]Out of that one is attached with the hydrogen and three valency is open, that is methenyl group.
[0:49]Methylene group that is CH2 compound, methyl group that is CH3 compound, apart from that hydroxyl methyl that is CH2OH, formyl group that is CHO group and formimino group that is CHNH.
[1:04]These six are the most important one carbon group which are present in our body and very useful for the various reaction in our body.
[1:10]So, in detail of this one carbon pool that we will look, but to understand this one carbon metabolism simply you have to remember from where we are getting this one carbon molecule, means one carbon donor or generator.
[1:21]Second thing how it is transported. So, one carbon is transported with the help of which molecule that is called a carrier molecule of the one carbon and exactly where it is utilized, so that is utilization of one carbon molecule.
[1:33]So, one by one we will look. First of all formyl THFA, means this one carbon group that is formyl group that is CHO, which is generated with the help of formic acid or the formate or particularly amino acid tryptophan.
[1:48]So, you have to remember tryptophan is donating or generating formyl THFA.
[1:51]It is sometime asked in the exam or MCQ formyl THFA is generated with the help of which protein or which amino acid, that is you have to remember tryptophan.
[2:00]Now, formyl group is nothing but a CHO group.
[2:04]This formyl group is utilized for the various purpose.
[2:07]First of all, second carbon of purine is generated with the help of formyl THFA.
[2:11]From this formyl THFA, it can be converted into the carbon dioxide and water and that can be exited out.
[2:16]Apart from that, methionyl tRNA, particularly formyl methionyl tRNA formation, this formyl tetrahydrofolic acid is utilized.
[2:26]So, these three are the particular utilization of the formyl THFA.
[2:29]Carbon dioxide generation and exation out, second carbon of the purine, formyl methionyl RNA generation.
[2:35]Now, from this formyl THFA, it can generate formimino THFA and it is reversible reaction.
[2:40]Apart from that formyl, another source of this formimino formation, that is histidine.
[2:47]Histidine, that is also a amino acid.
[2:50]So, that will generate formimino THFA, so it is a generator of the one carbon group.
[2:54]So, histidine generate formimino group and that will attach over the tetrahydrofolic acid.
[2:59]This THFA that is co-enzyme of the folic acid and this folic acid will attach over the formimino and that will be further utilized for the various reaction.
[3:07]So, you have to remember tryptophan will donate formyl THFA.
[3:10]Histidine is donating formimino THFA.
[3:14]Histidine have a group that is imidazole and it is generating formimino.
[3:18]I for imidazole and I for the formimino group that you have to remember.
[3:22]So, formimino is nothing but CHNH group.
[3:26]Now, from this formimino, one more one carbon group is generated, that is methenyl THFA.
[3:31]Methenyl is nothing but only CH group.
[3:34]So, CH that is called methenyl THFA, so that methenyl THFA that is generated from the formimino THFA and this methenyl THFA is also utilized for the eighth carbon of the purine.
[3:45]Purine that is adenine and guanine. So, second carbon is with the help of formyl THFA, eighth carbon with the help of methenyl tetrahydrofolic acid.
[3:53]Now, from the methenyl, now we will going to understand about methylene and methyl group.
[3:59]But it is somewhat complicated, but here we will try to understand very easily methenyl.
[4:02]But before that methenyl, we will try to understand first hydroxyl methyl THFA.
[4:09]So, this hydroxyl methyl is nothing but CH2OH.
[4:13]Means OH means hydroxyl group is attached over the methyl molecule that is CH3.
[4:16]Now, one hydrogen instead of that OH group is there, so it is called CH2OH.
[4:21]This hydroxyl methyl group that is generated from the choline, serine and glycine.
[4:27]Now, this glycine, serine and choline all are connected.
[4:30]And how it is connected that also we will look in this video. So, first you have to remember glycine, serine and choline.
[4:36]These three are generating hydroxyl methyl tetrahydrofolic acid.
[4:40]So, hydroxyl methyl group is generated from this particular amino acid plus choline and that will attach over the tetrahydrofolic acid and finally make hydroxyl methyl THFA.
[4:48]Now, from this hydroxyl methyl THFA, methylene THFA is generated.
[4:53]Now, this methylene is also generated from the methenyl THFA.
[4:58]So, one more use of methenyl THFA that is methylene THFA and methylene is also generated from the hydroxyl methyl tetrahydrofolic acid.
[5:06]Now, this methylene that will be further utilized for the same from where we are getting that is serine, glycine, choline.
[5:12]And same glycine and serine as well as choline that can also helpful to that can be generated with the help of this one carbon group that is methylene tetrahydrofolic acid.
[5:22]So, you have to remember glycine, serine and apart from that methylene tetrahydrofolic acid is also utilized for the deoxy TMP.
[5:30]UMP and TMP already you are knowing that pyrimidine monophosphate, that is uridine monophosphate and thymidine monophosphate.
[5:37]So, this TMP, deoxy TMP is generated with the help of methylene THFA.
[5:43]So, if this molecule is not there, then DNA formation can be affected.
[5:46]So, you have to remember methylene THFA is important molecule for the generation of TMP.
[5:52]Otherwise, glycine and serine is also formed with the help of this methylene tetrahydrofolic acid.
[5:55]So, that is methylene is nothing but a CH2 group.
[5:59]Now, finally remaining most important one carbon group that is methyl group.
[6:03]So, methyl group that is also attached over the tetrahydrofolic acid.
[6:08]But this methyl group that is donated or transfer with the help of vitamin B12 and methionine.
[6:13]So, how methionine and vitamin B12 will play role in this one carbon group that also we will look.
[6:19]Currently you have to remember this all formyl, formimino, methenyl, hydroxyl methyl are all diverted to the methenyl group and this methenyl is finally converted into the methyl tetrahydrofolic acid.
[6:30]Methyl means CH3 group.
[6:33]Now, these methyl THFA that will be helpful for the various transmethylation reaction, means again from serine to choline formation.
[6:39]Here we have seen that glycine and serine.
[6:42]So, same this methyl THFA is also utilized for the choline formation.
[6:46]So, these three are the donor as well as generator of the, these three are the particular generator of the one carbon group and these three are also produced from this one carbon group.
[6:55]So, simply that glycine, serine and choline that is donating one carbon group as well as they will accept and they will be regenerate as a glycine, serine and choline.
[7:04]Apart from that, creatine, epinephrine is also produced with the help of methyl tetrahydrofolic acid.
[7:10]And most importantly, homocysteine to methionine formation with the help of vitamin B12, that is cobalamin.
[7:18]So, that also we will look in this one carbon molecule. So, this picture, if you understand this picture, then whole one carbon metabolism is very easy.
[7:24]So, first of all you have to remember tryptophan or formate that is donating formyl THFA, histidine is helping to make formimino THFA, serine, glycine and choline that is making hydroxyl methyl THFA.
[7:37]And these all are utilized for the second carbon and eighth carbon of purine, formyl methionyl tRNA, glycine, serine and T deoxy TMP means thymidine monophosphate formation, serine, choline, creatine, epinephrine and methionine formation.
[7:49]Now, further in detail of this one carbon metabolism that we will look. So, one carbon group, except CH3 group, are carried by the tetrahydrofolic acid.
[7:57]We have seen that methyl THFA is generated, but further that will be occur or process or reaction will occur with the help of vitamin B12.
[8:04]So, you have to remember apart from this methyl THFA, all are transfer with the help of folic acid.
[8:10]So, most important transporter of one carbon group that is folic acid.
[8:14]Now, only methyl THFA that will be further convert into the methyl cobalamin.
[8:18]So, THFA is produced from folic acid and mostly fifth and tenth nitrogen of this THFA means tetrahydrofolic acid carry one carbon group.
[8:28]So, one carbon group is transfer with the help of this fifth nitrogen and tenth nitrogen.
[8:35]So, sometime it is attached over the only fifth position or sometime it is attached over the only tenth position or sometime in between these two.
[8:41]So, that is folic acid and over that that is convert into the THFA that is tetrahydrofolic acid and this THFA is the main transporter of the one carbon group that you have to remember.
[8:53]So, it is also asked which vitamin is responsible for the one carbon metabolism, so that is folic acid.
[8:58]Now, further how exactly this one carbon group is utilized in various reaction.
[9:03]First of all you have to remember when serine decarboxylation reaction is occur, serine is simple a hydroxyl group containing amino acid.
[9:10]From the serine, carbon dioxide molecule is removed, so it is called decarboxylation reaction and it is convert into the ethanolamine.
[9:16]So, already we have seen ethanolamine in a phosphatidylethanolamine that is a one of the important molecule, which is present in a phospholipid also present phosphatidylethanolamine present over in the cell membrane.
[9:28]So, ethanolamine will be further convert into the methyl ethanolamine with the attachment of the methyl group.
[9:34]One more methyl group will attach so it will convert into dimethyl ethanolamine.
[9:39]Further, that is addition of the methyl group. Further over that, one more methyl group will be attached and finally formation of choline.
[9:46]So, now you are knowing that from the serine, ethanolamine and ethanolamine is finally convert into the choline, that is same choline which is used in a acetyl choline or acetyl choline neurotransmitter.
[9:57]So, serine that is important amino acid from that ethanolamine and choline is generated.
[10:01]Now, you have to also remember you have seen that phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine in a classification of phospholipid.
[10:11]So, you never forget about that these all are connected molecule.
[10:14]So, all these phospholipid are also connected, means phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine.
[10:20]Now, here what happening, this one carbon group is accepted.
[10:23]Means serine to ethanolamine formation, ethanolamine to finally methyl ethanolamine, dimethyl ethanolamine and trimethyl ethanolamine, which is called a choline, that all are produced by accepting one methyl group.
[10:35]So, that is called a one carbon pool acceptor.
[10:38]So, they are accepting one carbon group. Now, from this choline, it is further convert into the betaine.
[10:44]So, here that water molecule is removed, so that is particular CH2OH, that is now convert into the CHO group.
[10:50]So, this CHO group is generated, now it is making trimethylglycine.
[10:54]Now, from this trimethylglycine, one carbon group that will be go back in a one carbon pool.
[11:00]So, here what happened, betaine is convert to dimethylglycine, but here one methyl group is go back in a one carbon pool.
[11:07]From this dimethylglycine, it is convert into the sarcosine, which is which is called as methylglycine.
[11:12]And finally from this methylglycine, glycine is regenerated.
[11:16]Now, that all are donating one carbon group.
[11:19]So, one carbon group which is utilized here for the formation of serine to choline and same thing will be reverse from choline to glycine formation.
[11:27]So, that is reversal of this choline pool or it is reversal of the one carbon pool.
[11:32]Now, glycine and serine have also connection. So, glycine can simply convert into the serine with the help of adding of this carboxyl or COOH group and also we have seen in protein metabolism how glycine is convert into the serine.
[11:44]So, glycine can be convert into the serine.
[11:47]So, here that whole process is a cyclic.
[11:50]So, here what happened, this one carbon group is utilized.
[11:53]Here whatever the molecule of one carbon group is utilized is going back.
[12:00]So, that is main reaction of the one carbon pool. So, up to here that all are utilized and here whatever the molecule of one carbon group is utilized is going back.
[12:11]As the serine is converted to choline, three one carbon units are utilized.
[12:16]During the conversion of choline to glycine, these methyl groups are recovered.
[12:20]Hence this pathway is called "SALVAGE PATHWAY" for one carbon units.
[12:30]Now, for further in this one carbon metabolism, all one carbon group are ultimately converted into the methyl THFA.
[12:36]So, we have seen that formyl THFA formimino THFA and finally generation of the methyl THFA.
[12:41]This is because, the reductase reaction is an irreversible step.
[12:45]So, finally once that formyl from this formyl THFA to finally formation of this methyl THFA, then it will be further metabolize with the help of vitamin B12.
[12:54]Now, from methyl THFA, the B12 co-enzyme accepts the methyl group to form methyl cobalamin.
[13:03]Cobalamin that is vitamin B12 and that will accept methyl group so it is finally make methyl cobalamin.
[13:10]It then transfers the methyl group to homocysteine to form methionine.
[13:15]So, methionine is generated from the homocysteine.
[13:18]So, methionine is one of the important sulfur containing amino acid, which is generated with the help of transfer of the methyl group from this methyl cobalamin and finally it is form with the help of homocysteine.
[13:28]But in B12 deficiency, deficiency of folic acid is also observed and this is because the transfer of methyl group from the methyl tetrahydrofolic acid does not occur.
[13:38]So, how exactly this reaction is occurring that we are going to understand.
[13:41]So, THFA is not regenerated and it is called folate trap.
[13:44]So, what is folate trap, how methionine is generated and how vitamin B12 is working in this one carbon metabolism, that we are going to understand from this particular picture.
[13:54]So, first of all you have to remember methyl THFA.
[13:57]So, we have seen in that particular picture how methyl tetrahydrofolic acid is generated.
[14:02]I have said that this methyl THFA is not actually transferring methyl group.
[14:06]So, because this methyl THFA has to transfer this methyl group to the vitamin B12, that is cobalamin.
[14:12]So, this methyl THFA is converted into the THFA with the help of vitamin B12.
[14:17]So, it will accept methyl group. So, methyl B12 is finally converted to the methyl cobalamin.
[14:23]Now, when it is converted, so THFA will be free. Now, this free THFA that can be further utilized for the one carbon transformation.
[14:30]Now, this methyl cobalamin that will convert homocysteine to the methionine by donating this methyl group.
[14:36]So, methyl cobalamin will donate the methyl group. So, homocysteine is converted to methionine and again regeneration of vitamin B12.
[14:44]Now, this vitamin B12 again convert this methyl THFA into the THFA.
[14:48]So, that is cyclic reaction, but here both the thing is important, vitamin B12 is most important and that is helping to convert homocysteine into methionine.
[14:56]Homocysteine is very dangerous molecule because it is one of the important molecule which is responsible for a heart attack in younger age group.
[15:04]So, here you have to remember vitamin B12 is also required to decrease this level of the homocysteine.
[15:10]Now, methionine is also related with the transfer of the methyl group.
[15:14]M for methionine, M for methyl group that you have to remember.
[15:17]But how it will transfer methyl group that we will look. So, this methionine, first it need to be activated and this activation will occur with the help of ATP.
[15:26]So, ATP from that phosphate will be removed, means total three phosphate, triphosphate, so three phosphate is removed, so this adenosyl group is attached and finally make S-adenosylmethionine, so that is called as SAM.
[15:37]S-adenosylmethionine.
[15:41]Now, this S-adenosylmethionine that will be further convert into the S-adenosylhomocysteine by donating this methyl group and this methyl acceptor will accept this methyl group and finally convert into the methylated product like creatine, epinephrine formation.
[15:55]But here S-adenosylmethionine is convert to the S-adenosylhomocysteine.
[16:00]Here what happened, that adenosyl group is present.
[16:03]So, that will be removed from this S-adenosylhomocysteine, so adenosine is removed and finally converted into the homocysteine.
[16:09]So, here all this methyl group transfer this vitamin B12 and methionine both are playing important role.
[16:16]So, suppose that vitamin B12 is not present, then what happen?
[16:20]This methyl THFA will not work to donate this methyl group.
[16:24]So, in the deficiency of vitamin B12, indirectly deficiency of folic acid is also observed, because once that methyl THFA.
[16:32]So, it is trap, it is further not convert into the tetrahydrofolic acid.
[16:35]So, folic acid level is decrease or it is found to be decrease, all its function will be affected.
[16:40]So, indirectly deficiency of folic acid is also observed and that is called folate trap.
[16:44]So, that you have to remember.
[16:54]Basically this whole process is most important for the formation of various methylated product, also to explain this folate trap.
[17:02]So, if this reaction will not occur in the deficiency of vitamin B12 and that is simply called folate trap and if vitamin B12 deficiency that is also responsible for increased concentration of homocysteine.
[17:13]So, you have to remember three thing. First this metabolic reaction that is helping to explain how methylated product is generated.
[17:20]Further importance of vitamin B12 to decrease homocysteine level, also importance of vitamin B12 to prevent folate trap in relation to the methyl tetrahydrofolic acid.
[17:30]So, basically this utilization of one carbon group are for the formation of following compound, means second and eighth carbon of the purine, formylation of methionyl tRNA, glycine molecule, serine as well as choline.
[17:42]These three are the important which are generated from this, so one carbon group is generated from this glycine, serine and choline, as well as these three molecule can be also produced with the help of this one carbon molecule.
[17:54]Apart from that deoxy TMP which is utilized for the particular DNA formation, further transmethylation reaction like important molecule creatine and epinephrine formation.
[18:03]Creatine is generated with the help of three amino acid, glycine, arginine and methionine, epinephrine which is produced from the norepinephrine.
[18:09]Apart from that, this one carbon that is also excitated in the form of carbon dioxide.
[18:14]So, that's all about the one carbon molecule or one carbon metabolism.
[18:17]So, how it is generated, how it is transported with the help of folic acid, as well as you have to remember vitamin B12 and it is which is utilized this one carbon group, which is utilized for the formation of these much of molecule.
[18:29]So, that's all about the one carbon molecule or one carbon metabolism.
