This composite image of the protein β -
galactosidase shows how cryo - EM has progressed over the years, from the indistinct blobs once obtained with the technique (left) to the nearly 2 - Å - resolution structures possible today (right).
In vitro, Pds has been
shown to produce β - glucosidase, N - acetyl - β - glucosaminidase, acid and alkaline phosphatases, esterase / esterase lipase / lipase, leucine and vailine arylamidase, naphthol - AS - B1 - phophohydrolase, various proteinases (albumin / casein / gelatin), and urease, while no enzymatic activity was indicated for cystine arylamidase, α - chymotrypsin, alpha / beta
galactosidase, trypsin, β - glucoronidase, α - fucosidase, and α - mannosidase [11].