Gastric proteases in the human infant.
The electrophoretic mobilities of proteases present in gastric juice taken within 10 h of birth from 5 healthy, premature infants were compared with calf chymosin, pig pepsin A and human adult gastric juice. The juice from 2 infants contained predominantly a chymosin-like enzyme, another had almost exclusively pepsins similar to those of the adult juice, while the other two contained a mixture of both. The pepsins consisted of two elements, probably pepsin A (EC 3.4.23.1), and pepsin C (EC 3.4.23.3). Single radial immunodiffusion gave a definite reaction to calf anti-chymosin serum in five samples taken from a further 17 infants. These results indicate that some human infants secrete chymosin. The reaction in the immunodiffusion assay indicated a much lower enzyme activity than that implied from electrophoretic separations. It is suggested that species differences resulted in poor cross-reactivity of the antiserum.
D012085:Chymosin / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D005750:Gastric Juice / Q000201:enzymology*; D005865:Gestational Age; D006801:Humans; D005779:Immunodiffusion; D007231:Infant, Newborn; D010434:Pepsin A / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*
D010447:Peptide Hydrolases; D010434:Pepsin A; C020557:gastricsin; D012085:Chymosin