Argininosuccinate lyase

ASL (argininosuccinate lyase) is a human gene that makes the protein argininosuccinate lyase, one of the enzymes controlling a series of reactions called the urea cycle. The ASL enzyme starts the reaction in which the amino acid arginine, a building block of proteins, is produced from argininosuccinate:

The urea cycle is a sequence of reactions in the cells of the liver. It processes excess nitrogen, generated when protein is used by the body, to make a compound called urea that is excreted by the kidneys. Eliminating the excess nitrogen in this way prevents it from accumulating in the form of ammonia, which is toxic.

The ASL gene is located on chromosome 7 between the centromere (junction of the long and short arm) and the long (q) arm at position 11.2, from base pair 64,984,963 to base pair 65,002,090.

ASL is related to intragenic complementation.

Related conditions
Argininosuccinic aciduria is associated with ASL.

Several different mutations in the ASL gene have been identified.

A mutated ASL gene may make an argininosuccinate lyase enzyme that is shorter than normal or the wrong shape.

The shape of an enzyme affects its ability to bring other substances together to start a chemical reaction. If the argininosuccinate lyase enzyme is misshapen, it cannot fulfill its role in the urea cycle. Excess nitrogen is not converted to urea for excretion, and toxic ammonia accumulates in the body.