Arginase I, Human, mAb D1.2

Monoclonal antibody D1.2 reacts specifically with Arginase I, the final enzyme in the urea cycle, which
is responsible for the hydrolysis of arginine to urea and ornithine. The highest concentration of the
enzyme is present in the liver in which the bulk of ureagenesis occurs. Two types of arginases are
known: Arginase I and II. The cytosolic enzyme found primarily in liver is Arginase I, a 35 kD protein
that circulates as trimer. Arginase II is exclusively located in the mitochondrion. Arginase I is next to the
liver in man also expressed by mature fetal and adult red blood cells and activated monocytic cells.
During inflammation induction of Arginase I by inflammatory cytokines in monocytic cells is considered
to lead to a local depletion of arginine resulting in a microenvironment that prevents nitric oxide
production and arginine dependent T cell function. Arginase II is expressed by kidney, nucleated red
blood cells, brain, spinal cord, gastro-intestinal tract, mammary gland and prostate. Enhanced
circulating Arginase I levels have been reported after surgery, following haemorrhage and in asthmatic
patients. Measurement of circulating Arginase I has been used experimentally as rapid marker for liver
injury.