Following the digestion of milk proteins from mother to baby.
Little is known about the digestive process in infants. In particular, the chronological activity of enzymes across the course of digestion in the infant remains largely unknown. To create a temporal picture of how milk proteins are digested, enzyme activity was compared between intact human milk samples from three mothers and the gastric samples from each of their 4-12 day postpartum infants, 2 h after breast milk ingestion. The activities of 7 distinct enzymes are predicted in the infant stomach based on their observed cleavage pattern in peptidomics data. We found that the same patterns of cleavage were evident in both intact human milk and gastric milk samples, demonstrating that the enzyme activities that begin in milk persist in the infant stomach. However, the extent of enzyme activity is found to vary greatly between the intact milk and gastric samples. Overall, we observe that milk-specific proteins are cleaved at higher levels in the stomach compared to human milk. Notably, the enzymes we predict here only explain 78% of the cleavages uniquely observed in the gastric samples, highlighting that further investigation of the specific enzyme activities associated with digestion in infants is warranted.
UCD Conway Institute of Biomolecular and Biomedical Research/School of Medicine and Medical Sciences/UCD Complex and Adaptive Systems Laboratory, University College Dublin , Dublin 4, Republic of Ireland.
Thérèse A
TA
Holton
Vaishnavi
V
Vijayakumar
David C
DC
Dallas
Andrés
A
Guerrero
Robyn A
RA
Borghese
Carlito B
CB
Lebrilla
J Bruce
JB
German
Daniela
D
Barile
Mark A
MA
Underwood
Denis C
DC
Shields
Nora
N
Khaldi
D002402:Cathepsin D / Q000378:metabolism; D002918:Chymotrypsin / Q000378:metabolism; D004063:Digestion; D010450:Endopeptidases / Q000378:metabolism; D005260:Female; D005341:Fibrinolysin / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D007441:Intubation, Gastrointestinal; D013058:Mass Spectrometry; D008894:Milk Proteins / Q000378:metabolism*; D008895:Milk, Human / Q000201:enzymology / Q000378:metabolism*; D009035:Mothers; D010196:Pancreatic Elastase / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D010455:Peptides / Q000032:analysis / Q000378:metabolism*; D059748:Proteolysis; D040901:Proteomics / Q000379:methods; D013270:Stomach / Q000201:enzymology; D014357:Trypsin / Q000378:metabolism
D008894:Milk Proteins; D010455:Peptides; D010450:Endopeptidases; D002918:Chymotrypsin; D010196:Pancreatic Elastase; D014357:Trypsin; D005341:Fibrinolysin; D010434:Pepsin A; D002402:Cathepsin D
digestive enzymes; enzyme activity; human milk; indigenous enzymes; infant digestion; milk enzymes; proteolytic enzymes