ratelimitingenzyme gluconeogenesis?

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ratelimitingenzyme gluconeogenesis?

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maoudoody
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07/27/08 - 03:09 PM

what is the rate limiting enzyme of gluconeogenesis?

pepck or fructose 1-6 biphosphatase

as kaplan and first aid mentioned different things?

cooolguy
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07/27/08 - 09:58 PM

f16b phosphatase

usmlekiller
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07/28/08 - 05:31 AM

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bioguy
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07/28/08 - 06:37 AM

all three - PEPCK, PC and F16diphoshatase are rate-limiting

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bioguy
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07/28/08 - 07:01 AM

Found this in this forum

1. Rate-limiting enzyme of fatty acid biosynthesis: acetyl CoA Carboxylase
2. Rate-limiting enzyme of cholesterol biosynthesis: HMG-CoA Reductase
3. Rate limiting step of B-oxidation: the carnitine shuttle it self : levels of malonyl CoA
4. Rate limiting enzyme of catecholamine synthesis: tyrosine hydroxylase
5. Rate limiting enzyme of Kreb's cycle: iso citrate dehydrogenase
6. Rate limiting enzyme of heme synthesis: delta-aminolevulinate synthase (ALA)
7. Rate limiting enzyme of urea cycle: carbamoyl phosphate synthetase-1
8. Rate limiting enzyme of glycolysis: phosphofructokinase (PFK)
9. Rate limiting enzyme of de novo purine synthesis: PRPP amidotransferase
10. Rate limiting enzyme of HMP-shunt: glucose-6-P-dehydrogenase (G6PD)

11. de novo Pyrimidine synthesis - Carbamoyl Phosphate Synthetase II

12. Ketone synthesis - HMG CoA lyase

Edited by bioguy on 07/29/08 - 01:47 PM

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maoudoody
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07/28/08 - 07:03 AM

bioguy wrote:
all three - PEPCK, PC and F16diphoshatase are rate-limiting

what is the source of this information? smiling face

bioguy
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07/28/08 - 07:03 AM

What the heck does "Rate-limiting" mean?

Is it only a bottleneck in the pathway, or any step that is regulated by allosteric and regulatory factors is rate-limiting?

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bioguy
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07/28/08 - 07:17 AM

maoudoody wrote:

what is the source of this information? smiling face

don' know, man! just came out of my mind. i had this notion that any step that is highly regulated is rate-limiting.

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maoudoody
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07/29/08 - 03:36 AM

any other inputs........inclined to be convinced by what bioguy said

bioguy
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07/29/08 - 01:45 PM

#10

maybe not Pyruvate Carboxylase, because the Oxaloacetate made in this reaction can also be used in TCA cycle, Transaminations reactions etc etc .

so PEPCK and F16BPase can be considered as rate-limiting.

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hitesh
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07/29/08 - 07:34 PM

#11

Rate limiting step = slowest step... 'cos thats what will decide the overall kinetics of the net reaction.. (just like the slowest car in a lane will decide the speed at which traffic moves in that lane) Only one step can be the "slowest"

For gluconeogenesis, it's F1,6 bisphosphatase..

Among the three pathways for gluconeogenesis i.e. PEPCK, lactate and from amino acids; the PEPCK pathway is the slowest.

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maoudoody
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07/30/08 - 05:22 AM

#12

so both of them or pepck

kaplan says pepck where first aid frructose 16 biphosphatase

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