Bromelain

Bromelain is the name given to the crude extract of pineapple stem and fruit. It is mainly a mixture of thiol (cysteine) endopeptidases — enzymes that cut proteins within the chain — together with smaller amounts of other components, including phosphatases, glucosidases, peroxidases and cellulases.^[1]

Stem bromelain (EC 3.4.22.32) and fruit bromelain (EC 3.4.22.33) are prepared differently and have different enzyme compositions; the word “bromelain” usually means stem bromelain.^[1]

Bromelain comes from the pineapple, Ananas comosus — the leading edible member of the plant family Bromeliaceae, grown in tropical and subtropical countries. Commercially, it is prepared from cooled pineapple juice by centrifugation, ultrafiltration and freeze-drying, which yields a yellowish powder.^[1]

Bromelain belongs to the protease family — enzymes that hydrolyse the peptide bonds holding proteins together. Proteases are grouped by their catalytic mechanism into types including serine and cysteine proteases; bromelain is a plant cysteine protease, whereas the dog’s own pancreatic proteases such as trypsin are produced by the body.^[1],[2]

Its activity is typically measured against protein substrates such as casein or gelatin, and it works across a pH range of roughly 5.5 to 8.0.^[1]

The label lists six enzymes in the Digestive Enzyme Complex, 150 mg in total, derived from natural plant sources. The label states that total for the complex as a whole; it does not give a separate amount for each enzyme, so we don’t either. Bromelain is named on the DIGEST+ label as its own ingredient, alongside the more general “protease”.