[Nitrogen fractions of human milk during the first week of lactation. Comparison of milk from mothers of term and premature newborn infants]. / Etude des fractions azotées du lait de femme pendant la première semaine de la lactation. Comparaison des laits de mères de nouveau-nés à terme et prématurés.

Nitrogen fractions in human milk (total nitrogen, non protein nitrogen, casein nitrogen and soluble protein nitrogen) were determined by direct dosage or by calculation during the first 7 days of lactation in 61 mothers feeding artificially. Twenty-five delivered at term and 36 prematurely. In all cases a decrease in all nitrogen fractions was observed. The amounts of total nitrogen and soluble proteins were similar in both groups. A difference in the distribution of the nitrogen fractions occurs only on the 8th day following delivery. Milk from mothers who deliver prematurely contains more casein and less non protein nitrogen amounts.

[Primary structure of the casein macropeptide of porcine and human kappa caseins]. / Structure primaire du caséinomacropeptide des caséines kappa porcine et humaine

The amino acid sequence of porcine and human caseinomacropeptides (CMP), the C-terminal glycopeptide released from kappa-casein by chymosin at the initial step of milk coagulation, have been investigated. The complete amino acid sequence of porcine CMP and that of the first 59 amino acid residues of human CMP have been determined. Porcine and human CMPs contain 71 and likely 65 amino acid residues respectively. The extra hexapeptide 38-43 found in porcine CMP arises obviously from the duplication of the DNA fragment coding for the 6 preceding amino acids.