Difference Between Cystine and Cysteine

Amino acids are organic compounds that are combined in long chains to form proteins, which are the basis of all biological processes and are absolutely necessary for each of the metabolic processes that occur in humans. These amino acids, also known as the building blocks of proteins, can be mainly divided into two types of amino acids based on their use and importance. Amino acids that can be produced within the body are called non-essential amino acids and amino acids that cannot be produced in the human body are called essential amino acids. Cystine and cysteine ​​are two of the amino acids that often leave people confused, since cystine is composed of cysteine ​​and when required, cystine can revert back to cysteine. Both the amino acids cystine and cysteine ​​contain sulfur and are known as semi-essential and non-essential amino acids, respectively. The main difference between them is the components behind their formation; Cysteine ​​is derived from the amino acid methionine with the collaboration of vitamins such as B-12 and B-6, while cysteine ​​is formed when two cysteine ​​molecules combine and the oxidation process occurs.

Comparison chart

What is cystine?

Enzyme that is an oxidized dimer of cysteine. It is formed when two cysteine ​​molecules combine and the oxidation process takes place. Although it can be recovered to cysteine ​​as required. It is a sulfur-containing amino acid that is more stable than cysteine ​​and helps form healthy skin, hair, and bones.and connective tissues. Cystine plays a prominent role in protein synthesis and also helps determine the final shape of the protein. It is considered as the semi-essential amino acid, which means that it can be essential or not. There are about 20 kinds of amino acids needed in the human body, of which they are essential as the cells of the human body cannot generate them. Namely, the essential enzymes required in the human body are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.

What is cysteine?

A sulfur-containing amino acid that is derived from the amino acid methionine with the help of vitamins such as B-12 and B-6, and is found in keratins and other proteins is called cysteine. Its constituent, methionine, is itself an essential amino acid, although cysteine ​​is the non-essential amino acid. After its formation, cysteine ​​undergoes several processes to produce the antioxidant glutathione and the amino acid taurine. If a person is low on cysteine, the body does not produce the glutathione needed to stay healthy. Although cysteine ​​is grouped as a non-essential amino acid, in rare cases, cysteine ​​may be essential for infants, the elderly, and people suffering from malabsorption syndromes.

Cystine vs Cysteine

• Cysteine ​​is derived from the amino acid methionine with the help of vitamins such as B-12 and B-6, while cystine is formed when two cysteine ​​molecules combine and the oxidation process takes place.
• Cystine is considered a semi-essential amino acid, while cysteine ​​is said to be a non-essential amino acid.
• Cystine is more stable than cysteine.
• Cystine is less soluble than cysteine.
• Cystine helps form healthy skin, hair, bone, and connective tissues, while cysteine ​​produces the antioxidant glutathione and the amino acid taurine.