Involved in the degradation of isopropylamine, which is a constituent of the herbicides atrazine. Catalyzes the ATP-dependent formation of gamma-glutamyl-isopropylamide from isopropylamine and L-glutamate. It can also use aminoalkanes, amino-alcohols (L-alaninol and D-alaninol) and amino-esters as substrates. ATP + isopropylamine + L-glutamate = ADP + gamma-L-glutamyl-isopropylamide + H(+) + phosphate Cells lacking this gene are unable to transform isopropylamine to L-alaninol. Belongs to the glutamine synthetase family.