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Niacin Vitamin B3

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0. 4-Methyl-5-hydroxyethyl-thiazole. Methylene bridge. THIAMIN (VITAMIN B1) ... synthesis ??? catabolism ??? amino acids. ??? enzyme glycogen phosphorylase ?? ... – PowerPoint PPT presentation

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Title: Niacin Vitamin B3


1
THIAMIN (VITAMIN B1)
4-Methyl-5-hydroxyethyl-thiazole
2,5-Dimethyl-6-aminopyrimidine
Methylene bridge
????? http//www.indstate.edu/thcme/mwking/vitam
ins.html
2
Coenzyme Form ??? Thiamin
Thiamin pyrophosphate (active form)
????? http//www.indstate.edu/thcme/mwking/vitam
ins.html
reactive group
????? Lehninger et al, 1993
3
Thiamin
ATP - dependent thiamin pyrophosphotransferase (
brain, liver )
Thiamin pyrophosphate (TPP)
  • ???? coenzyme ??? enzymes pyruvate
    dehydrogenase,
  • a - ketoglutarate dehydrogenase ???
    transketolase
  • ?????????????????? pentose phosphate
    pathway

4
????? Lehninger et al, 1993
5
VITAMIN B6
????? Murray et al, 1996
6
Pyridoxal Pyridoxine Pyridoxamine
Pyridoxal phosphate (major form ??? vitamin
B6)
Enzyme Mg2, ATP requiring enzyme,
pyridoxal kinase
7
Phosphorylation ??? Pyridoxal ??? Pyridoxal Kinase
????? Murray et al, 1996
8
?????????? Pyridoxal Phosphate
  • ???? coenzyme ??? enzymes ???????????????
  • ????????? transamination ?? ???????
  • synthesis ??? catabolism ??? amino acids
  • ??? enzyme glycogen phosphorylase ??
  • ??????? glycogenolysis

9
Folic Acid (F)
1
2
3
9
10
4
glutamic acid
p-aminobenzoic acid
2-amino-4-oxo-6-methylpterin
Active form ???? coenzyme form ???
tetrahydrofolate(FH4 ???? H4)
????? http//www.indstate.edu/thcme/mwking/vitam
ins.html
10
TETRAHYDROFOLATE
Function ??? tetrahydrofolate ???? carrier ???
one carbon
group
????? Nelson and Cox, 2000
11
????? Murray et al, 1996
12
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13
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14
Folate Derivative
????? http//www.indstate.edu/thcme/mwking/vitam
ins.html
15
????? Murray et al, 1996
16
One Carbon Transfer Reactions
????????????????? biosynthesis ??? serine ,
methionine, glycine,
choline, purine nucleotides ??? dTMP
dUMP
dTMP
N5,N10- Methylene FH4
FH2
FH4
reductase
17
??????? methyl group ??? N5,N10-methylene FH4
????? dUMP ?????????????? dTMP ??? dihydrofolate
????? Murray et al, 1996
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