Difference Between Cystine and Cysteine

Main Difference

Amino Acids are the organic compounds that combine in long chains to form proteins, which are the bases of around all biological processes as they are absolutely necessary for every of the metabolic processes happening in the human being. These amino acids also referred as the building blocks of protein can be mainly divided into two types of amino acids depending upon their usage and importance. The amino acids which can be produced within the body are called nonessential amino acids and the amino acids which can’t be produced within the human body are named essential amino acids. Cystine and Cysteine are the two of the of the amino acids which left people often confused as cystine is made up of cysteine and when required cystine can get back as the 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 constituents behind their formation; cysteine is derived from amino acid methionine with collaboration of vitamins like B-12 and B-6, whereas cystine is formed when two molecules of cysteine combine together and process of oxidation takes place.

Comparison Chart

CystineCysteine
FormationCystine is formed when two molecules of cysteine combine together and process of oxidation takes place.Cysteine is derived from amino acid methionine with collaboration of vitamins like B-12 and B-6.
TypeSemi-essential Amino AcidNon-essential Amino Acid
StableMoreLess
SolubleLessMore
FormsCystine helps to form healthy skin, hair, bones, and connective tissues.Cysteine produces the antioxidant glutathione and the amino acid taurine.

What is Cystine?

An enzyme which is an oxidized dimer of cysteine. It is formed when two molecules of cysteine combine together and process of oxidation takes place. Although it can bounce back to cysteine upon requirement. It is a sulfur-containing amino acid, which is more stable than the cysteine and helps to form healthy skin, hair, bones, and connective tissues. Cystine has a prominent role in protein synthesis and it also helps to determine the protein’s final shape. It is regarded as the semi-essential amino acid which means it may be essential or may not be essential. There are around 20 types of amino acids required in human body, out of them are essential as human body cell can’t generate them. Namely the essential enzymes required in human body are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.

What is Cysteine?

A sulphur-containing amino acid which is derived from amino acid methionine with collaboration of vitamins like B-12 and B-6, and occurs in keratins and other proteins is called cysteine. The constituent of it, methionine is itself an essential amino acid, though cysteine is the non essential amino acid. After its formation, cysteine undergoes several process to produce the antioxidant glutathione and the amino acid taurine. If indvidual is low on cysteine, the body fails to produce required glutathione to keep you healthy. Although cysteine is grouped as a non-essential amino acid, in rare cases, cysteine may be essential for infants, the elderly, and individuals suffering from the malabsorption syndromes.

Cystine vs. Cysteine

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

Comparison Video

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Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White

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