Qhov sib txawv tseem ceeb ntawm oxidative thiab nonoxidative pentose phosphate txoj kev yog oxidative pentose phosphate txoj kev tsim nicotinamide adenine dinucleotide phosphate (NADPH). Meanwhile, nonoxidative pentose phosphate txoj kev tsim cov suab thaj pentose.
Txoj kev pentose phosphate yog txoj hauv kev metabolic uas tshwm sim rau tib lub sijhawm glycolysis. Nws muaj ob txoj kev sib txawv raws li oxidative pentose phosphate txoj kev thiab nonoxidative pentose phosphate txoj kev. NADPH yog tsim nyob rau hauv oxidative theem, thaum pentose qab zib yog generated los ntawm lub non-oxidative theem. Ntxiv nrog rau cov suab thaj pentose thiab NADPH, txoj hauv kev no tsim cov ribose 5-phosphate, uas yog ib qho precursor rau nucleotide synthesis.
Oxidative Pentos Phosphate Pathway yog dab tsi?
Oxidative pentose phosphate txoj kev yog thawj ntawm ob theem ntawm txoj kev pentose phosphate. Lo lus "oxidative" tau muab rau theem no txij li thaum oxidation tshwm sim nyob rau hauv txoj kev no, thiab tsawg kawg yog ib qho hluav taws xob raug tshem tawm hauv txhua qhov tshuaj tiv thaiv. Cov theem oxidative pib nrog kev hloov pauv ntawm qabzib 6 phosphate mus rau 6-phosphogluconolactone los ntawm ib qho enzyme hu ua qabzib 6-phosphate dehydrogenase.
Daim duab 01: Oxidative Phase ntawm Pentose Phosphate Pathway
Lub sijhawm hloov pauv no, ib lub molecule ntawm NADPH (txo qhov sib npaug) yog tsim los ntawm kev noj cov hluav taws xob tso tawm. Tom qab ntawd 6-phosphogluconolactone hloov mus rau 6-phosphogluconate los ntawm 6-phosphogluconolactonase. Thaum kawg, 6-phosphogluconolactonase hloov mus rau hauv ribulose 5-phosphate los ntawm ib qho enzyme hu ua 6-phosphogluconate dehydrogenase, ua rau lwm cov molecule ntawm NADPH. Yog li ntawd, thaum kawg ntawm oxidative theem, qabzib 6 phosphate hloov mus rau hauv Ribulose 5-phosphate, tsim ob lub molecules ntawm NADPH. NADPH yog siv los txo qis biosynthesis hauv hlwb, xws li fatty acid synthesis.
Nonoxidative Pentose Phosphate Pathway yog dab tsi?
Nonoxidative pentose phosphate txoj kev yog theem ob ntawm PPT. Ribulose 5-phosphate (uas yog cov khoom kawg ntawm oxidative theem) yog qhov pib ntawm nonoxidative pentose phosphate txoj kev. Cov theem nonoxidative pib nrog kev hloov pauv ntawm ribulose 5 phosphate mus rau ribose 5-phosphate los ntawm ribose-5-phosphate isomerase thiab ribulose 5 phosphate rau hauv xylulose 5-phosphate los ntawm ribulose 5-phosphate 3-epimerase. Tom qab ntawd, ob qho khoom siv no tau hloov mus rau glyceraldehyde 3-phosphate thiab sedoheptulose 7-phosphate los ntawm transketolase. Tom qab ntawd cov enzyme hu ua transaldolase hloov lawv mus rau hauv erythrose 4-phosphate thiab fructose 6-phosphate.
Daim duab 01: Oxidative Phase ntawm Pentose Phosphate Pathway
Thaum kawg, xylulose 5-phosphate thiab erythrose 4-phosphate hloov mus rau glyceraldehyde 3-phosphate + fructose 6-phosphate los ntawm transketolase. Cov khoom ntawm nonoxidative pentose phosphate txoj kev yog siv nyob rau hauv lub synthesis ntawm nucleotides thiab aromatic amino acids.
Dab tsi zoo sib xws ntawm Oxidative thiab Nonoxidative Pentos Phosphate Txoj Kev?
- Oxidative thiab nonoxidative pentose phosphate txoj kev yog ob theem ntawm PPT.
- Lawv tshwm sim hauv cytoplasm ntawm cov hlwb.
- Theem oxidative yog ua raws li theem uas tsis yog oxidative.
- ATP tsis tsim lossis siv ob theem.
- Theem nonoxidative siv cov khoom ntawm oxidative theem.
Qhov txawv ntawm Oxidative thiab Nonoxidative Pentos Phosphate Pathway yog dab tsi?
Theem oxidative yog thawj theem ntawm pentose phosphate txoj hauv kev uas cov piam thaj 6 phosphate hloov mus rau hauv ribulose 5 phosphate los ntawm kev tsim NADPH. Lub sijhawm no, lub sijhawm no, yog theem ob ntawm pentose phosphate txoj hauv kev uas ribulose 5 phosphate hloov mus rau fructose-6-phosphate thiab glyceraldehyde-3-phosphate. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm oxidative thiab nonoxidative pentose phosphate txoj kev. Cov khoom ntawm oxidative theem, NADPH, pab tsim lwm cov molecules thaum cov khoom ntawm nonoxidative theem, ribose-5-phosphate qab zib, yog siv los ua DNA thiab RNA.
Ntxiv mus, tag nrho cov tshuaj tiv thaiv ntawm oxidative theem yog qabzib 6-phosphate + 2 NADP+ + H2O → ribulose 5- phosphate + 2 NADPH + 2 H+ + CO2, thaum tag nrho cov tshuaj tiv thaiv ntawm nonoxidative theem yog 3 ribulose-5-phosphate → 1 ribose- 5-phosphate + 2 xylulose-5-phosphate → 2 fructose-6-phosphate + glyceraldehyde-3-phosphate. Yog li, qhov no kuj yog qhov sib txawv ntawm oxidative thiab nonoxidative pentose phosphate txoj kev.
Cov hauv qab no qhia txog qhov sib txawv ntawm oxidative thiab nonoxidative pentose phosphate txoj kev.
Summary – Oxidative vs Nonoxidative Pentos Phosphate Pathway
Oxidative thiab nonoxidative yog ob theem sib txawv ntawm txoj kev pentose phosphate. Oxidative txoj kev yog thawj theem thiab nws ua raws li cov theem uas tsis yog oxidative. NADPH yog tsim thaum lub sij hawm oxidative pentose phosphate txoj kev thiab cov tshuaj tiv thaiv tsis thim rov qab. Nyob rau hauv sib piv, pentoses yog tsim thaum lub sij hawm nonoxidative pentose phosphate txoj kev thiab cov tshuaj tiv thaiv yog thim rov qab. Cov khoom ntawm txoj kev pentose phosphate muaj txiaj ntsig zoo hauv ntau txoj kev. Hauv qhov no, ribose-5-phosphate qab zib siv los ua DNA thiab RNA thaum NADPH molecules uas pab tsim lwm cov molecules. Yog li, qhov no yog cov ntsiab lus ntawm qhov sib txawv ntawm oxidative thiab nonoxidative pentose phosphate txoj kev.
