Glutathione synthetase (GSS) (EC 6.3.2.3) is the second enzyme in the glutathione

Glutathione

Glutathione is a tripeptide that contains an unusual peptide linkage between the amine group of cysteine and the carboxyl group of the glutamate side-chain...

 biosynthesis pathway. It catalyses the condensation of gamma-glutamylcysteine

Gamma-Glutamylcysteine

γ-Glutamylcysteine is a precursor of glutathione. It is formed by gamma-glutamylcysteine synthetase and used by glutathione synthetase to form glutathione....

 and glycine

Glycine

Glycine is an organic compound with the formula NH2CH2COOH. Having a hydrogen substituent as its 'side chain', glycine is the smallest of the 20 amino acids commonly found in proteins. Its codons are GGU, GGC, GGA, GGG cf. the genetic code.Glycine is a colourless, sweet-tasting crystalline solid...

, to form glutathione.

In eukaryotes, this is a homodimeric enzyme. In humans, defects in GSS are inherited in an autosomal recessive way and are the cause of severe metabolic acidosis

Metabolic acidosis

In medicine, metabolic acidosis is a condition that occurs when the body produces too much acid or when the kidneys are not removing enough acid from the body. If unchecked, metabolic acidosis leads to acidemia, i.e., blood pH is low due to increased production of hydrogen by the body or the...

, 5-oxoprolinuria, and increased rate of haemolysis and defective function of the central nervous system

Central nervous system

The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

. The substrate-binding domain has a 3-layer alpha/beta/alpha structure

Secondary structure

In biochemistry and structural biology, secondary structure is the general three-dimensional form of local segments of biopolymers such as proteins and nucleic acids...

.