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Streptococcus thermophilus STH450 had a very high oxygen uptake. This strain was then compared with aerobic metabolism to S. thermophilus ATCC 19258, a reference strain for aerobic metabolism. Molecular oxygen, which was absorbed by S. thermophilus STH450 during aerobic glycolytic metabolism, was involved in the oxidation of NADH by the catalytic activity of NADH oxidase. The portion of pyruvate that corresponded to the oxidized NADH was committed to form alpha-acetolactate, acetoin, and diacetyl. Both strains were deficient in peroxidase and pyruvate oxidase activities; therefore, NADH oxidase was probably the terminal oxidase in aerobic glycolytic metabolism. Oxygen uptake and NADH oxidase activities were significantly higher in S. thermophilus STH450 than in S. thermophilus ATCC 19258. alpha-Acetolactate, acetoin, and diacetyl also accumulated during aerobic glycolytic metabolism of S. thermophilus STH450. However, when both strains were grown in the presence of pyruvate, these metabolites were equivalent. Hence, less oxygen might be needed for pyruvate metabolism.

An enzymatic hydrolysate of bovine casein were studied for molecular size and antigenic properties. As determined by Sephadex G-25 gel filtration, polypeptide fractions having molecular weights greater than 1,000 were not detected in the soluble fraction of the casein hydrolysate. Antigenicity of the fraction was not detected by heterologous passive cutaneous anaphylaxis in guinea pig-rabbit antiserum system mediated by immunoglobulin G types of antibody (guinea pig passive cutaneous anaphylaxis) and its inhibition test. Furthermore, it was not detected by rat long latency homologous mediated by immunoglobulin E antibody and its inhibition test. To prepare anticasein immunoglobulin E serum for rat long latency homologous passive cutaneous anaphylaxis, immunization of rats was by single subcutaneous injection of casein with aluminum hydroxide. Antiserum with highest passive cutaneous anaphylaxis titer (1:64) against bovine casein was obtained by a dose of 2,000 micrograms of the protein at day 12.

Superoxide dismutase (SOD, BC 1.15.1.1) catalyses the dismutation of the superoxide anion and is a metalloenzyme ubiquitous to living organisms. The enzyme is also contained in bovine milk and has been suggsted to diminish the oxidative problems associated with the superoxide anion. The present study is an attempt to determine the concentration of SOD in human colostrum and in mature milk to make a comparison with the values in bovine milk and human blood. Human colostrum and mature milk samples were respectively collected from 15 and 12 healthy lactating women at Machida Municipal Hospital and those living in Machida-shi. The samples immediately cooled in a refrigerator (at less than 5°C), skimmed by centrifugation at 1500 x 9 for 20 min and stored at-80°C until being assayed.

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