Bile salt-dependent lipase (or BSDL), also known as carboxyl ester lipase (or CEL) is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. ...
produced by the adult
pancreas
The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an end ...
and aids in the digestion of fats. Bile salt-stimulated lipase (or BSSL) is an equivalent enzyme found within
breast milk
Breast milk (sometimes spelled as breastmilk) or mother's milk is milk produced by mammary glands located in the breast of a human female. Breast milk is the primary source of nutrition for newborns, containing fat, protein, carbohydrates ( l ...
. BSDL has been found in the pancreatic secretions of all species in which it has been looked for. BSSL, originally discovered in the milk of humans and various other
primate
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including human ...
s, has since been found in the milk of many animals including dogs, cats, rats, and rabbits.
Enzymatic activity
More than 95% of the fat present in human milk and in infant formulas is in the form of
triacylglycerol
A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and '' glyceride'').
Triglycerides are the main constituents of body fat in humans and other vertebrates, a ...
s (TG).
In adults, TGs are thought to be broken down or
hydrolyzed
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.
Biological hydrolysis ...
mainly by the
colipase-dependent lipase (CDL) enzyme. In the newborn, CDL activity in the
duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestin ...
is lower than in adults.
[
Both BSDL and BSSL have a broad substrate specificity and, like CDL, are capable of hydrolyzing triacylglycerides (in addition to ]phospholipid
Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipi ...
s, ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glyceride ...
s of cholesterol
Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...
, and lipid-soluble vitamins). In particular, they can hydrolyze esters of the essential fatty acids (n-3 and n-6 PUFAs) and DHA.[*] BSDL production in the newborn pancreas is quite low when compared with production in the mammary gland
A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in prim ...
or adult pancreas.[Maggio L, Bellagamba M. ''et al.']
A prospective, randomized, double-blind crossover study comparing rhBSSL (recombinant human Bile Salt Stimulated Lipase) and placebo added to infant formula during one week of treatment in preterm infants born before 32 weeks of gestational age.
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References
Further reading
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External links
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{{Esterases
Milk
Enzymes