Abstract
In order to explore the cell characteristics obtained from the bovine dental sac and papilla, the alkaline phosphatase (ALPase) was biochemically characterized. Bovine permanent tooth germs were classified into the following three stages; Stage I: tooth germ which has slight dentin formation; Stage II: about half of the root was formed; and Stage III: full length of the root was almost completed.
Bovine tooth germs (incisors) from 2-year-olds were dissected immediately after slaughtering and were separated into dental sac and papilla. Subsequently, individual tissue was digested with collagenase at 37°C for 90 min. The ALPase activity was determined using the modified Lowry method, and expressed as units per 1×105 cells. One unit of activity represents 50 nmole of p-nitrophenylphosphate hydrolized/15 min at 37°C.
Cells from the dental sac have a high ALPase activity which increased according to the developing stages of the tooth germs; Stage I: 44.3±1.9; Stage II: 59.0±3.2; and Stage III: 67.6±4.9 units. However, the ALPase activity of dental papilla cells was maintained at a constant level. Km value of the dental sac at pH 10.15 was calculated as 2.86 mM for Stage I and 1.18 mM for Stage II and III respectively. However, the dental papilla cells kept the same Km value of 2.0 mM throughout the three stages. The ALPase was also inhibited markedly by l-homoarginine and slightly by l-phenylalanylglycylglycine.
Therefore, ALPase seems to be an important marker enzyme for development of the dental sac in comparison with that of the dental papilla.
