What is Bromelain?
Bromelain is a proteolytic, or protein-digesting, enzyme derived from pineapple stems. It’s designed by nature to help support gastrointestinal function, and may also help to promote the comfort of muscles and joints.
How is Bromelain measured?
Put your thinking cap on, this is going to be technical!
The measurement of enzymatic activity is very complex. Proteolytic enzymes can be standardized using different activity-measuring units, including Milk Clot Units (MCU/mg), Casein Digestion Units (CDU/mg), Bromelain Tyrosine Units (BTU/gram), Rorer units, FCC Papain units (PU), and more.
One FCC Papain Unit (PU), for example, is defined as that quantity of enzyme that liberates the equivalent of 1 µg (or mcg – microgram) of tyrosine per hour under the conditions of the assay. This procedure is sometimes used to determine the proteolytic activity of bromelain. The assay is based on a 60-minute proteolytic hydrolysis of a casein substrate at pH 6.0 and 40° C. Soluble casein is then measured spectrophotometrically.
GDU/gram is another measurement of protein digestion (in this case gelatin) by an enzyme, and is a different way to show how much protein an enzyme can digest in a specific time under specific conditions.
Bromelain can come in various strengths, and weights per serving in a formula, affecting the values shown on the labels. For example, some Bromelain has a documented enzyme activity of 2400 GDU/gram, so 500 mg (500 milligrams, equal to half a gram) of this material would have 1200 GDU enzyme activity per capsule (2400 GDU/gram times 0.5 grams = 1200 GDU per capsule).
Similarly, the rated activity of the enzyme used, multiplied by the weight in grams, provides the enzyme activity shown on the product label for other strengths of the enzyme per gram. Since there are variations in how concentrated (GDU/gram) the enzymes are in a raw material like Bromelain, the weight of the enzyme alone does not accurately measure the strength of that enzyme in a formula.
How can I compare various ways of measuring Bromelain?
Different activity-measuring methods can use various protein substrates. Since enzymes are specific to peptide bonds, as well as which terminal end of an amino acid it will cleave, there typically will not be a precise conversion between measures – unless both assays are performed on the same material to allow a valid comparison. This is why conversion among different enzyme measures can be so difficult to obtain. We do have an approximate conversion for Bromelain: Bromelain at 2000 GDU/g would be about equal to 30,000,000 FCC PU/g potency.