Nucleotides vs Amino Acids - BOC Sciences (2025)

Loading...

The interaction between biological macromolecules represented by protein-nucleic acids plays an important regulatory role in life activities, and participates in biological processes such as the replication and transmission of cellular genetic information, cell metabolism, material transportation and signal transduction. Nucleic acids and proteins are composed of nucleotides and amino acids respectively. They are carriers of genetic information and executors of biological functions. Nucleotides ensure the storage and transfer of genetic information when building DNA and RNA; amino acids are the cornerstone of proteins and participate in many biological processes such as catalysis, signal conduction, and structural building.

Nucleotide definition and structure

Nucleotides are compounds composed of bases (purine or pyrimidine), ribose or deoxyribose, and phosphate. They constitute the basic units of ribonucleic acid (RNA) and deoxyribonucleic acid (DNA), and their arrangement carries the transmission and expression of genetic information.

The phosphate group is connected to adjacent nucleotides through phosphodiester bonds, forming the backbone structure of the nucleic acid chain. Nitrogen-containing bases are divided into two categories: purines (adenine A and guanine G) and pyrimidines (cytosine C, thymine T and uracil U). In DNA, A pairs with T and C pairs with G; in RNA, A pairs with U. The pairing between bases maintains the double helix structure of nucleic acid through hydrogen bonds, ensuring the stability and transmissibility of genetic information.

Amino acid definition and structure

Amino acids are a class of organic compounds containing amino and carboxyl groups, which are connected by a central carbon atom (alpha carbon), to which a hydrogen atom and a variable side chain (R group) are attached. The general chemical formula is R-CH (NH₂)-COOH, where R stands for different side chain groups, and the differences in this group give each amino acid its unique properties. There are 20 common amino acids in nature, which are like the building blocks of life, connected by peptide bonds to form polypeptide chains, which in turn build complex and diverse protein molecules.

There are 20 kinds of amino acids that make up human protein, of which 8 amino acids cannot be synthesized by the human body itself and must be supplemented from exogenous sources, which are called essential amino acids, including lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, valine (and histidine is also needed for infants and young children). Rather than essential amino acids, the body can use other substances to synthesize, but in specific physiological conditions, such as disease, growth and development peak, appropriate external supplementation also helps to maintain body balance. In addition, although some amino acids can be synthesized by the human body, they cannot meet normal needs under special circumstances, which are called semi-essential amino acids or conditionally essential amino acids.

20 amino acids at BOC Sciences

What's the difference between amino acids and nucleotides?

Function of nucleotide

1. Genetic information transfer: Nucleotides are the basic building blocks of DNA and RNA, and they store and transmit genetic information in a specific sequence. DNA, as the main carrier of genetic information, stores genetic instructions precisely through base sequences to guide protein synthesis and cell function regulation. RNA acts as a messenger, carrying genetic information from DNA to ribosomes in the cytoplasm, directing protein synthesis. In addition, nucleotides are also involved in the synthesis of RNA and DNA and are key substances for the replication and expression of genetic information.

2. Energy metabolism: Nucleotides play a central role in energy metabolism, especially as carriers of high-energy molecules. For example:

ATP (adenosine triphosphate): As the main energy molecule in cells, it releases energy through hydrolysis to power biochemical reactions.

NAD+ (nicotinamide adenine dinucleotide): As a coenzyme involved in a variety of metabolic reactions, such as REDOX reactions.

Other nucleotide derivatives, such as GTP, UTP, etc., are also involved in specific metabolic pathways such as glycogen synthesis and the tricarboxylic acid cycle.

Nucleotides, through the transfer and transformation of their phosphate groups, provide the necessary energy support for energy conversion and metabolic activities in the cell.

3. Signal transmission: Nucleotides and their derivatives play an important regulatory role in cell signaling, mainly as follows:

Second messengers: such as cAMP (cyclic adenylate) and cGMP (cyclic guanosine), these nucleotide derivatives regulate intracellular signaling pathways by activating specific enzymes or receptors, thereby influencing cell behavior.

Regulation of enzyme activity: Certain nucleotides can alter the conformation or activity of enzymes, thereby regulating metabolic pathways or signaling pathways.

Immune response: Nucleotides improve body resistance by stimulating immune cells, enhancing immune activity and cell number.

Related products at BOC Sciences

Function of amino acid

1. Building blocks of protein synthesis: Proteins are the main carriers of life activities, from actin and myosin for muscle contraction, to enzymes that catalyse biochemical reactions, to antibodies against pathogens, all of which are built from amino acids. For example, the globin part of hemoglobin is composed of a variety of amino acids arranged in an orderly manner, responsible for the transport of oxygen, to ensure the respiratory energy supply of tissues and cells throughout the body.

2. Energy supply source: When the body is in a state of energy scarcity such as hunger and long-term exercise, amino acids can be converted into glucose through gluconeogenesis, providing energy support for the brain, nervous system and other important organs, and maintaining the basic metabolism of the body.

3. Precursors of neurotransmitters: Some amino acids participate in the synthesis of neurotransmitters. For example, tryptophan is the raw material for the synthesis of serotonin (5-hydroxytryptamine), serotonin plays a key role in regulating mood, sleep, appetite, and its level imbalance is closely related to depression, anxiety and other mental disorders; Tyrosine can be converted into catecholamine neurotransmitters such as dopamine and epinephrine, which affect motor control, stress response and attention.

4. Maintain nitrogen balance: Nitrogen is crucial in human metabolism, after the intake of protein is decomposed into amino acids, the body uses its nitrogen source to synthesize its own substances, and excess nitrogen is excreted in the form of urea. Under normal circumstances, the intake and discharge of nitrogen in the human body maintain a dynamic balance, which is inseparable from the precise regulation of amino acids to ensure the smooth renewal and repair of body tissues.

Synthesis and metabolism of nucleotide

Nucleotide synthesis can be divided into two pathways: de novo synthesis and salvage pathway.

De novo synthesis pathway: This pathway progressively builds nucleotides from simple molecules. The synthesis of purine nucleotides begins with the formation of phosphoribose pyrophosphate (PRPP), followed by a series of enzymatic reactions to gradually construct purine rings. Important intermediates include 5-phosphoribonamine and inosine acid (IMP), the latter of which can be further converted into adenine nucleotides and guanine nucleotides. The synthesis of pyrimidine nucleotides is similar, starting with carbamyl phosphate and aspartic acid and eventually forming uridine monophosphate (UMP), which can subsequently be converted into other pyrimidine nucleotides.

Salvage synthesis pathway: This pathway takes recovered nucleosides and bases and converts them into nucleotides. This pathway is energy efficient for cells, using bases from cellular protein breakdown or diet.

Degradation of deoxynucleotides: Deoxynucleotides are produced by reduction of the corresponding ribonucleotide diphosphate. It is catalyzed by ribonucleoside diphosphate reductase. dTMP is formed by methylation of dCMP.

The metabolism of nucleotides also involves the breakdown of nucleotides into simple molecules that can be used in basic metabolism, such as uric acid (the end product of purine metabolism) or β-alanine (the product of pyrimidine metabolism), through steps such as dephosphorylation, deamination, and modification of the base ring or sugar ring.

Amino acid synthesis and metabolism

Direct synthesis: Amino acids can be produced through direct synthesis, such as glycine, alanine, etc. The synthesis of these amino acids usually relies on intermediates in the central metabolic pathway, such as oxaloacetate, pyruvate, alpha-ketoglutarate, etc.

Transamination: Transamination is an important step in amino acid synthesis. It transfers amino groups from one amino acid to a keto acid to produce new amino acids. For example, glutamic acid can be transaminated to produce aspartic acid, while oxaloacetate can be converted to aspartic acid.

Mutual conversion of amino acids: Amino acids can be transformed into each other through a series of enzymatic reactions. For example, glycine can produce serine, aspartic acid and glutamine through a series of reactions.

Essential amino acids cannot be synthesized in the human body and must be ingested from the diet.

The decomposition of amino acids usually first removes the amino group to form a carbon skeleton-a-keto acid. Amino, urea or other nitrogen-containing compounds a-keto acid. The degradation reactions of amino acids mainly include: deamination, decarboxylation, hydroxylation and other effects.

(1) Deamination

Oxidative deamination: Glu dehydrogenase, one of the enzymes that oxidizes specific amino acids.

Transamination: It is an important way of deamination of amino acids and is achieved through transaminases. Co-factors for these enzymes include pyridoxal phosphate (PLP) and pyridoxamine phosphate (PMP).

Combined deamination: Combined deamination with transaminase-Glu dehydrogenase, combined deamination with transaminase-purine nucleotide cycle.

Deamidation: Glutaminase and asparaginase cause amide to produce corresponding amino acids and ammonia.

(2) Decarboxylation: Amino acids are decarboxylated under the catalysis of decarboxylase (pyridoxal phosphate is a coenzyme) to produce amine compounds and CO2.

(3) Urea cycle: Most terrestrial vertebrates exclude the amino nitrogen produced by decomposition in the form of urea. Urea cycle: The cycle that converts ammonia to urea is the earliest discovered metabolic cycle. One molecule of urea is formed through the urea cycle, which removes two molecules of amino nitrogen and one molecule of CO2; urea is a neutral and non-toxic substance; urea-depleting animals synthesize urea in the liver.

(4) Metabolism of amino acid carbon skeleton: The carbon skeleton produced by amino acid degradation finally produces seven main intermediate metabolites: pyruvate, oxaloacetate, fumaric acid, succinylCoA, a-ketoglutaric acid, acetyl CoA, and acetoacetate.

What is the relationship between amino acids and nucleotides?

Hydrogen bond and electrostatic interaction: The sugar rings and bases in nucleotides can hydrogen bond or interact electrostatic with amino acids. For example, adenine (A) binds to glycine (Gly) by hydrogen bonds, while guanine (G) preferentially binds to arginine (Arg).

There are also electrostatic interactions between the side chains of amino acids (such as the guanidine group of arginine) and the phosphate groups of nucleotides, and this interaction helps stabilize the protein-nucleic acid complex.

Hydrophobic interaction: Hydrophobic side chains of amino acids (e.g., leucine Leu, isoleucine Ile) can hydrophobic interact with the sugar ring or phosphate group of nucleotides, thereby enhancing the binding stability of the complex.

Polarity interaction: Polar amino acids (such as serine Ser, threonine Thr) have polar interactions with the sugar ring or phosphate group of nucleotides through their hydroxyl or amino groups, and this interaction is particularly common in RNA-protein complexes.

Non-covalent interaction: The non-covalent interactions between nucleotides and amino acids include hydrogen bonding, electrostatic interaction, hydrophobic interaction and polar interaction. Together, these interactions determine the binding affinity and stability of the protein-nucleic acid complex.

Transmission and expression of genetic information: The nucleotide sequence determines the encoded information of mRNA, and mRNA guides the sequence of amino acids in proteins through the process of transcription and translation. This process is central to the transmission of the genetic information of life.

Protein synthesis and regulation: As a key molecule in the translation process, trnas carry specific amino acids and complement the nucleotide sequence on the mRNA, thus ensuring the accuracy of protein synthesis. Amino acid metabolites, such as glutamic acid, are involved in nucleotide synthesis, maintaining the balance between the two.

Molecular recognition and signal transduction: The interaction between nucleotides and specific amino acids plays an important role in molecular recognition. For example, certain proteins perform their functions by recognizing specific amino acid-nucleotide complexes. Interactions between amino acids and nucleotides are also involved in signaling processes, such as DNA repair enzymes that use amino acid-nucleotide stacking interactions to identify DNA damage.

Price Inquiry