Crystalline l-Aspartate β-Decarboxylase of Pseudomonas dacunhae

摘要: l -Aspartate β-decarboxylase ( -aspartate 4-carboxy-lyase) of Pseudomonas dacunhae has a molecular weight about 800,000. On treatment with 1 m guanidine the enzyme dissociates into subunits intermediate size (mol wt = 400,000, s 5.6 S). Removal by dialysis results in reassociation to native enzyme. Irreversible dissociation an ultimate subunit 100,000, s20,w0 6.9 S) occurs on 5 guanidine. presence 0.1 mercaptoethanol, this smaller polypeptide chains 50,000, 4.2 Aspartate contains 32 sulfhydryl groups per 800,000 g protein as determined titration p-chloromercuribenzoate The number half-cystine residues is 48 amino acid analysis. Also 8 disulfide molecule were found. Phenylthiocarbamylation apodecarboxylase urea gives 0.87 (corrected) mole serine phenylthiohydantoin hydrolysis, and hydrazinolysis 0.73 lysine 50,000 Digestion carboxypeptidase B 2 releases 0.98 evidence from these analyses suggests that consists 100,000 each composed two apparently identical 50,000) covalently linked through single linkage. Amino analysis also presented.