ACC oxidase an enzyme present in plant tissues that catalyses the Fe2+– and ascorbate-dependent oxidation of 1-aminocyclopropane-1- carboxylic acid (ACC) to ethylene, CO2, HCN, and H2O. It is a highly unstable monomer (35 kDa) that is inhibited by Co2+. Its activity increases under conditions of stress and at certain developmental stages (e.g. during fruit ripening).
abrin a highly toxic ∼65 kDa glycoprotein obtained from the seeds of jequirity, or Indian liquorice (Abrus precatorius L.), a tropical Asian vine that also occurs in Florida. It consists of an ∼30 kDa acidic A chain, and an ∼35 kDa neutral B chain, held together by disulfide bonds. The A chain is a powerful
abl an oncogene from murine Abelson leukemia virus. The human equivalent is ABL (locus at 9q34), which encodes a tyrosine protein kinase. In humans, inappropriate activation of ABL occurs via a reciprocal translocation between chromosomes 9 and 22 in which ABL is joined at the breakpoint cluster region (bcr) of the ph1 gene on chromosome