Polyamine profile in ovine and caprine colostrum and milk.

The objective of this study was to monitor the post-partum variation of polyamine content, in ovine and caprine milk, from indigenous Greek breeds. Twenty samples of ewe and 20 samples of goat colostrum and milk were collected at the 1st, 2nd, 3rd, 4th, 5th and 15th day post-partum. Putrescine, spermidine and spermine were measured as dansylated derivatives by high-performance liquid chromatography. Putrescine was the least concentrated of these substances in both milk types. Spermidine was the prevailing polyamine in caprine samples, reaching levels up to 4.41 µmol/l on the 3rd day post-partum. In ovine milk, the profile of the mean concentrations showed greater levels of spermine than spermidine, except for the 5th day post-partum. These data suggest that goat colostrum and ewe milk (15th day) could be considered as good natural sources for these bioactive growth factors, and may become useful raw materials for designing tailored dairy products for specific population groups.

Purification and characterization of chymosin and pepsin from kid.

The objective of this work was to study the characteristics of the gastric aspartic proteinases chymosin and pepsin which are constituents of the kid rennet. The two enzymes were extracted from abomasal tissue of one kid from a local indigenous breed, separated from each other by DEAE-cellulose chromatography and then were purified by gel filtration and anion-exchange chromatography. The molecular weights of the purified kid chymosin and pepsin as determined by gel filtration were 36 kDa and 40 kDa respectively. The isoelectric point of kid chymosin was as multiple forms of 3-6 zones at pH 4.6-5.1, while that of kid pepsin was at pH < or =3.0. Kid pepsin contained 0.37 molecules phosphorous per molecule and was totally inhibited by 5 muM pepstatin A, being more sensitive than kid chymosin. Both enzymes were almost equally as proteolytic as calf chymosin on total casein at pH 5.6. Kid pepsin activity was more pH and temperature dependent than kid chymosin activity. In comparison with the calf chymosin temperature sensitivity, the order of increased sensitivity was: calf chymosin