Lec 28 - Nucleotide: Purine Metabolism

These flashcards cover key vocabulary and concepts from the lecture on purine metabolism, focusing on biosynthesis, degradation, and regulation of nucleotides.

PRPP

5-Phosphoribosyl-1-pyrophosphate, an activated form of ribose-5-phosphate important for nucleotide biosynthesis.

Lesch-Nyhan syndrome

A disorder caused by a deficiency of hypoxanthine-guanine phosphoribosyltransferase (HGPRT), leading to increased uric acid levels and neurological symptoms.

Imp

Inosine monophosphate, a key precursor in the purine biosynthesis pathway for both AMP and GMP.

AMP Synthesis

A process in purine metabolism where aspartate condenses with IMP to form AMP, regulated by GTP.

GMP Synthesis

A process producing guanosine monophosphate from IMP via oxidative steps, regulated by feedback mechanisms.

Purine Salvage Pathway

A mechanism that recycles purine bases from nucleotides, allowing for efficient nucleotide synthesis.

Xanthine oxidase

An enzyme involved in the degradation of purines, specifically responsible for converting hypoxanthine and xanthine to uric acid.

Gout

A form of arthritis characterized by excess uric acid, leading to painful joint inflammation.

Uric Acid

A waste product formed from the degradation of purines, often measured in excess in conditions like gout.

PRPP Synthetase

An enzyme that synthesizes 5-phosphoribosyl-1-pyrophosphate, regulating the entry point of purine and pyrimidine synthesis.

Glutamine-PRPP Amidotransferase

An enzyme that catalyzes the first committed step in purine biosynthesis, converting PRPP and glutamine into 5-phosphoribosylamine.

IMP Dehydrogenase

An enzyme in the guanine biosynthesis pathway, converting IMP to XMP and regulated by its products.

Adenylosuccinate synthetase

An enzyme that catalyzes a step in AMP synthesis from IMP and is inhibited by AMP.

Urea

A waste product of protein metabolism, which is different from uric acid and more soluble.

Glutamine

An amino acid that serves as a nitrogen donor in several biosynthetic pathways, including purine synthesis.

Salvage pathway enzyme deficiency

Deficiencies that impair the recycling of purines, leading to diseases such as Lesch-Nyhan syndrome.

Guanine

One of the four main nucleobases in the nucleic acid of DNA and RNA, and a product of purine metabolism.

Hypoxanthine

A purine base that is a product of purine metabolism and a substrate in the salvage pathway.

Self-mutilation behavior

Behavioral symptoms associated with Lesch-Nyhan syndrome, including self-inflicted injuries.

10-Formyl tetrahydrofolate

A cofactor providing carbon atoms in the synthesis of nucleotides, specifically in purine metabolism.

Xanthine

A purine derivative, an intermediate in purine catabolism, that gets oxidized to uric acid.

Nucleotide

The basic structural unit of nucleic acids, consisting of a nitrogenous base, a sugar, and a phosphate group.

Allopurinol

A medication used to treat gout by inhibiting xanthine oxidase, decreasing uric acid production.

Hypoxanthine-guanine phosphoribosyltransferase (HGPRT)

An enzyme critical to the purine salvage pathway that converts hypoxanthine and guanine to IMP and GMP.

Nucleotide Biosynthesis

The complex process of creating nucleotides from simpler molecules, involving de novo synthesis and salvage pathways.

Uric acid crystals

Solid deposits of uric acid that can form in joints and tissues, causing gout attacks.

Purine Catabolism

The breakdown of purines to ultimately produce uric acid as a waste product.

Biochemical Regulation

Mechanisms that control enzymatic activities in metabolic pathways, ensuring appropriate responses to cellular conditions.

Adenosine Deaminase

An enzyme that catalyzes the deamination of adenosine, with a deficiency leading to severe combined immunodeficiency (SCID).

De novo synthesis

The process of synthesizing nucleotides from scratch, as opposed to rebuilding from existing bases.

Nucleotide Monophosphates

The simplest form of nucleotides, which can be recycled and utilized in nucleotide synthesis.

Clinical treatment of Gout

Often involves the use of xanthine oxidase inhibitors like allopurinol to manage uric acid levels.