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PathWhiz ID Pathway Meta Data

PW127299

Pw127299 View Pathway
disease

Adenine Phosphoribosyltransferase Deficiency (APRT)

Homo sapiens
Adenine phosphoribosyltransferase deficiency, which is also known as APRTD or APRT deficiency, is a rare inherited inborn error of metabolism (IEM) leading to the recurrent formation of kidney stones. It is an autosomal recessive disorder associated with a mutation in the enzyme adenine phosphoribosyltransferase (APRT). APRT is involved in the nucleotide salvage pathway, which provides an alternative, and energetically more efficient route to nucleotide biosynthesis in humans and most other animals. A defect in this enzyme can lead to the accumulation of the insoluble purine known as 2,8-dihydroxyadenine. In particular, when APRT has reduced or nonexistent activity, adenine accumulates which is then degraded by xanthine dehydrogenase to 2,8-dihydroxyadenine (DHA). 2,8-Dihydroxyadenine is a derivative of adenine which accumulates in 2,8 dihydroxyadenine urolithiasis (kidney stones). Kidney and urinary tract stones can obstruct the urinary tract, resulting in pain and difficulty urinating. If left untreated, the condition can eventually produce kidney failure. APRTD was first diagnosed in 1976. There are two categories of APRTD: type I involves a complete loss of the APRT function while type II involves a partial loss and is mostly found in Japan. APRT deficiency is estimated to affect 1 in 27 000 people in Japan. APRTD is rarer in Europe, where it affects 1 in 50 000 to 100 000 people. A diagnosis of APRTD can be made by analyzing kidney stones or measuring DHA concentrations in urine. APRTD is treatable with regular doses of allopurinol, which inhibits xanthine dehydrogenase activity. APRTD can also be treated with a low-purine diet and a high fluid intake.

PW121856

Pw121856 View Pathway
disease

Adenine Phosphoribosyltransferase Deficiency (APRT)

Mus musculus
Adenine phosphoribosyltransferase deficiency, which is also known as APRTD or APRT deficiency, is a rare inherited inborn error of metabolism (IEM) leading to the recurrent formation of kidney stones. It is an autosomal recessive disorder associated with a mutation in the enzyme adenine phosphoribosyltransferase (APRT). APRT is involved in the nucleotide salvage pathway, which provides an alternative, and energetically more efficient route to nucleotide biosynthesis in humans and most other animals. A defect in this enzyme can lead to the accumulation of the insoluble purine known as 2,8-dihydroxyadenine. In particular, when APRT has reduced or nonexistent activity, adenine accumulates which is then degraded by xanthine dehydrogenase to 2,8-dihydroxyadenine (DHA). 2,8-Dihydroxyadenine is a derivative of adenine which accumulates in 2,8 dihydroxyadenine urolithiasis (kidney stones). Kidney and urinary tract stones can obstruct the urinary tract, resulting in pain and difficulty urinating. If left untreated, the condition can eventually produce kidney failure. APRTD was first diagnosed in 1976. There are two categories of APRTD: type I involves a complete loss of the APRT function while type II involves a partial loss and is mostly found in Japan. APRT deficiency is estimated to affect 1 in 27 000 people in Japan. APRTD is rarer in Europe, where it affects 1 in 50 000 to 100 000 people. A diagnosis of APRTD can be made by analyzing kidney stones or measuring DHA concentrations in urine. APRTD is treatable with regular doses of allopurinol, which inhibits xanthine dehydrogenase activity. APRTD can also be treated with a low-purine diet and a high fluid intake.

PW144304

Pw144304 View Pathway
drug action

Adenine Drug Metabolism Action Pathway

Homo sapiens

PW002072

Pw002072 View Pathway
metabolic

Adenine and Adenosine Salvage III

Escherichia coli
Adenosine is first incorporated into the cytosol through either a nupG or a nupC transporter. Once in the cytosol, adenosine is degraded into adenine by reacting with a water and a adenosine nucleosidase, releasing a D-ribofuranose and a adenine. The adenine then reacts with a PRPP through a adenine phosphoribosyltransferase resulting in the release of a pyrophosphate and an AMP . The AMP in turn reacts with a water molecule through a AMP nucleosidase resulting in the release of a D-ribofuranose 5-phosphate and a adenine.

PW002071

Pw002071 View Pathway
metabolic

Adenine and Adenosine Salvage II

Escherichia coli
The salvage of adenine begins with adenine being transporter into the cytosol through a adeP hydrogen symporter. Once in the cytosol adenine is degraded by reacting with a ribose-1-phosphate through an adenosine phosphorylase resulting in the release of a phosphate and adenosine. Adenosine is then deaminated by reacting with water, a hydrogen ion and an adenosine deaminase resulting in the release of an ammonium and a inosine . Inosine can then be phosphorylated through an ATP driven inosine kinase resulting in the release of an ADP, a hydrogen ion and a IMP

PW002069

Pw002069 View Pathway
metabolic

Adenine and Adenosine Salvage I

Escherichia coli
The salvage of adenine begins with adenine being transporter into the cytosol through a adeP hydrogen symporter. Once in the cytosol adenine is degraded by reacting with a ribose-1-phosphate through an adenosine phosphorylase resulting in the release of a phosphate and adenosine. Adenosine is then deaminated by reacting with water, a hydrogen ion and an adenosine deaminase resulting in the release of an ammonium and a inosine . Inosine then reacts with a phosphate through a inosine phosphorylase resulting in the release of a ribose 1-phosphate and a hypoxanthine. Hypoxanthine reacts with a PRPP through a hypoxanthine phosphoribosyltransferase resulting in the release of a pyrophosphate and a IMP molecule.

PW144264

Pw144264 View Pathway
drug action

Ademetionine Drug Metabolism Action Pathway

Homo sapiens

PW000605

Pw000605 View Pathway
drug metabolism

Adefovir Dipivoxil Metabolism Pathway

Homo sapiens
Adefovir dipivoxil is an ester prodrug of adefovir, a nucleotide analogue used in the treatment of chronic hepatitis B. Adefovir dipivoxil is taken up into the liver cell and is cleaved into adefovir by intracellular esterases. Adefovir is subsequently phosphorylated first by adenylate kinases and then by nucleoside diphosphate kinases into adefovir diphosphate. Adefovir diphosphate is an analogue of deoxyadenosine triphosphate (dATP) and competes with dATP for binding to the viral DNA polymerase and subsequent incorporation into the growing DNA strand. Once incorporated into the DNA, adefovir causes chain termination, thus preventing viral replication.

PW144830

Pw144830 View Pathway
drug action

Adefovir dipivoxil Drug Metabolism Action Pathway

Homo sapiens

PW126450

Pw126450 View Pathway
drug action

Adefovir Dipivoxil Action Pathway (New)

Homo sapiens
Adefovir dipivoxil is a nucleotide analog used to treat chronic hepatitis B virus (HBV). When HBV infects a cell, the virus first binds and fuses with the cell, releasing its nucleocapsid containing its RNA and reverse transcriptase into the cytosol of the cell. The reverse transcriptase converts the viral RNA into viral DNA in the cytosol. The viral DNA goes to the nucleus through the nuclear pore complex where it undergoes the process of transcription. The new viral RNA formed from transcription is transported back to the cytosol through the nuclear pore complex and translation occurs to produce viral proteins. These viral proteins are assembled and new HBV viruses bud from the cell. Adefovir dipivoxil enters the cell and is metabolized to release adefovir by carboxylesterase enzyme. Adefovir is converted into adefovir monophosphate by adenylate kinases. Nucleoside diphosphate kinases then convert adefovir monophosphate into adefovir diphosphate. Adefovir diphosphate is an analog of deoxyadenosine-5'-triphosphate (dATP). Adefovir diphosphate inhibits the activity of HBV reverse transcriptase by competing with its substrate, dATP and by incorporation into viral DNA. Adefovir diphosphate lacks the 3'-OH group which is needed to form the 5′ to 3′ phosphodiester linkage essential for DNA chain elongation, therefore, once adefovir diphosphate gets incorporated into DNA, this causes DNA chain termination, preventing the growth of viral DNA. Less viral proteins are therefore produced, and there is a reduction in new viruses being formed.