L-asparaginase II (EcAII (in the context of Escherichia coli), AnsB (gene name))

L-asparaginase II is an enzyme encoded by the ansB gene in Escherichia coli and other bacteria. It catalyzes the hydrolysis of L-asparagine to L-aspartic acid and ammonia, a reaction crucial for nitrogen metabolism and exploited therapeutically to treat acute lymphoblastic leukemia (ALL). The enzyme is secreted, tetrameric, and displays higher substrate affinity than its cytoplasmic counterpart (L-asparaginase I). Its expression is tightly regulated by global transcription factors such as the cAMP receptor protein (CRP) and fumarate and nitrate reductase regulator protein (FNR), in response to carbon source and oxygen levels[1][2][3][4][8]. The bacterial L-asparaginase II (EcAII) is the most clinically used form of asparaginase, as it depletes extracellular L-asparagine, causing selective starvation and apoptosis of leukemic blasts. The primary clinical use is in chemotherapy for ALL; monitoring and management of adverse effects are required due to potential immunogenicity and toxicity. The gene product is well-characterized structurally and enzymatically, and the name "ansB gene product" specifically references the enzyme L-asparaginase II[2][4][6][8][9].

Other names

L-asparaginase IIasparaginase isozyme IIEcAIIansB gene productL-asparagine amidohydrolase

Depletes circulating L-asparagine by catalyzing its hydrolysis to L-aspartate and ammonia, depriving leukemia cells of an essential amino acid[2][8][9]