#Biochemistery
#Carbohydrate_metabolism
#بوست_رقم (10)
في البوست دا ح نتكلم عن
Uronic acid pathway
ودي النقاط اللي ح نتناولها
📌 Definition.
📌 Location.
📌 Steps.
📌 Fate of glucuronic acid.
📌 Defect.
كان اتكلمنا عنها كلام بسيط في بوست رقم (5) بس هسي ح ناخدها بالتفصيل ان شاء الله.
🌸 Definition:
It is a minor pathway for oxidation of glucose, in which glucose is converted into glucuronic acid.
🌸 Location:
Intracellular location: Cytosol.
Organ location: Mainly liver.
🌸 Steps:
موضحة تحت بالصورة 👇
🌸 Functions (importance) of uronic acid pathway:
Produces UDP-glucuronic acid, which is important for:
1. Synthesis of substrates:
a. Glycosaminoglycans.
b. Vitamin C, L-ascorbic acid (not in human).
2. Conjugation reactions:
Is used for conjugation with many body compounds to make them more soluble before excretion e.g. steroid hormons and bilirubin.
3. Detoxification reactions:
Is used for conjugation with toxic compounds to make them less toxic.
🌸 Fate of glucuronic acid:
تابعوا مع الصورة المرفقة تحت 👇
UDP-glucuronate is converted to glucuronate then —> L-xylulose —> D-xylitol —> D-xylulose —> which then joins pentose phosphate pathway to be completely oxidized.
🌸 Defect of uronic acid pathway:
Caused by enzyme defects and administration of certain drugs.
1. Essential pentosuria:
🍁inherited disorder.
🍁Rare disease.
🍁caused by: L-Xylitol Dehydrogenase.
Due to deficiency in this enzyme L-xylulose cannot be converted to Xylitol,
طيب ح ينتج لي من عدم التحول دا تراكم ل L-xylulose ويحصل ليه excretion في urine.
2. Oxalosis:
Caused by: Parenteral administration of Xylitol.
Involving calcium oxalate deposition in brain and kidney.this result from the conversion of D-xylulose to oxalate
التحول دا موضح في صورة تحت 👇
3. Effect of certain drugs:
Various durg markedly increase the rate at which glucose enters the uronic acid pathway such as:
Barbital or chlorobutanol , aminopyrine and antipyrine lead to increase the excretion of L-xylulose.
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