Occurrence of prochymosin variants in the abomasum of bovine foetuses and calves.
Prochymosin variants were analysed in single abomasa from 67 foetuses (3-9 months of gestation) and 33 calves (about 6 weeks old) of Black-and-White cattle collected in a slaughter house. The method of agarose gel electrophoresis followed by detection of proteolytic activity was used. Three distinct prochymosins A, B and C that occurred singly or in pairs (with equal proteolytic activities of both components) were found. Chymosin A, B and C obtained after conversion of corresponding prochymosins, demonstrated similar electrophoretical mobilities like the three chymosin fractions contained in commercial rennin (Sigma, USA). Our chymosin B showed identical mobility as the amidated form of recombined chymosin B contained in Chymogen (Chr. Hansen's Lab., Denmark A/S). Prochymosin A, B and C in the examined animals were precursors of corresponding chymosins and were controlled by three separate codominant alleles. The following prochymosin phenotypes were found: AA (30), AB (32), AC (4), BB (29), BC (4) and CC (1). Chi-square analysis demonstrated significant differences between the observed and expected numbers of phenotypes. The gene frequencies of prochymosin A, B and C were 0.48, 0.47 and 0.05, respectively.
Wiśliński
M
M
Department of Animal Physiology, Faculty of Veterinary Medicine, Agricultural University, Lublin, Poland.
Popielarz
M
M
D000018:Abomasum / Q000737:chemistry*; D000818:Animals; D000833:Animals, Suckling / Q000378:metabolism*; D002417:Cattle / Q000196:embryology / Q000378:metabolism*; D012085:Chymosin / Q000032:analysis* / Q000737:chemistry; D004792:Enzyme Precursors / Q000032:analysis* / Q000737:chemistry; D005260:Female; D005753:Gastric Mucosa / Q000737:chemistry; D008297:Male
D004792:Enzyme Precursors; C032443:prorennin; D012085:Chymosin