Antimetabolites in the body against vitamins

Overview of antimetabolites

1. ANTI-METABOLITES

2. CONTENTS
•INTRODUCTION
•USESOFANTI-METABOLITES
•OTHERFEATURESOFANTI-METABOLITES

3. ANTI-METABOLITES
•Antimetabolitesarethechemicalcompoundsthatblockthe
metabolicreactionsbytheirinhibitoryactiononenzymes.
•Antimetabolitesareusuallystructuralanaloguesofsubstratesandthusare
competitiveinhibitors.
•Theyareinuseforcancertherapy,goutetc.

4. •Antimetabolitesarestructurallyrelatedtothenormalcompoundsthatexist
withinthecell
•Antimetabolitesgenerallyinterferewiththeavailabilityofnormalpurineor
pyrimidinenucleotideprecursors,eitherbyinhibitingtheirsynthesisorby
competingwiththeminDNAorRNAsynthesis.
•TheirmaximalcytotoxiceffectsareinS-phase(therefore,cellspecific).

5. USESOFANTI-METABOLITES
•Aminopterin(4-aminofolicacid)andamethopterin(methotrexate)are
powerfulcompetitiveinhibitorsoffolatereductaseandTHFAgeneration.
•ThusthesedrugsdecreasetheDNAformationandcelldivision.Theyare
widelyusedasanti-cancerdrugs(antimetabolites),especiallyforleukemias
andchoriocarcinomas.Folinicacid(citrovorumfactor)isgiventorescuethe
patientfromtoxicityofmethotrexate.Methotrexateisalsousedintreatmentof
rheumatoidarthritisasanimmunosuppressant.
•Pyrithiamineandoxy-thiaminearethetwoimportantantimetabolitesof
thiamine.

6. TYPESOFANTIMETABOLITES
•Purineantagonist:6-Mercaptopurine(6-MP)
•Pyrimidineantagonist:5-fluorouracil(5-fu)
•Folateantagonist:Methotrexate

7. OTHERFEATURESOFANTI-METABOLITES
•Twoantimetabolitesusedintreatmentofviralinfections,acyclovirand
zidovudine(azidodeoxythymidine)areactivatedbyphosphorylationwithin
cellsinfectedwithviruses.

8. THANKYOU