Proenzyme of Manduca sexta phenol oxidase: purification, activation, substrate specificity of the active enzyme, and molecular cloning.

• DOI: 10.1073/pnas.92.17.7764
• Publication Date: 2006-05-31T13:17:17Z
• Authors: M Hall; T Scott; M Sugumaran; K Söderhäll; J H Law
• Keywords: Manduca; Hemolymph; Sphingidae; Mealworm

Phenol oxidase (PO) was isolated as a proenzyme (pro-phenol oxidase, pro-PO) from the hemolymph of Manduca sexta larvae and purified to homogeneity. Pro-PO exhibits M(r) 130,000 on gel filtration two bands with an apparent approximately 100,000 SDS/PAGE, well size-exclusion HPLC. Activation pro-PO achieved either by specific proteolysis cuticular protease or detergent cetylpyridinium chloride at concentration below critical micellar concentration. A cDNA clone for M. obtained larval hemocyte library. The encodes polypeptide 80,000 Da that contains copper-binding sites shows high sequence similarity POs, hemocyanins, storage proteins arthropods. Sexta pro-PO, together other arthropod pro-POs, short stretch amino acids thiol ester region alpha-macroglobulins complement C3 C4.