Exploration of genes and the functions affected by serum calcium-decreasing factor (caldecrin)

钙调蛋白是一种胰凝乳蛋白酶型丝氨酸蛋白酶，是我们从胰腺中分离纯化的降钙因子。钙调蛋白以前体形式合成并从细胞分泌。在研究钙调蛋白功能的过程中，我们发现：1）钙调蛋白抑制骨吸收，但不具有蛋白酶活性。对应于大鼠钙调蛋白的氨基酸序列（aa 71 -79）负责钙调蛋白对骨吸收的抑制。2)钙调蛋白在骨骼肌中有表达，其mRNA表达量随肌肉分化的进行而增加。3)钙调蛋白基因在出生后1-28天的大鼠脑中呈组成性表达。结果表明，在大鼠的嗅球、大脑、海马、丘脑和小脑等脑组织中均检测到钙调蛋白mRNA的表达，表明钙调蛋白是一种多功能蛋白酶。

Caldecrin, a serum calcium-decreasing factor that we purified from pancreas, is a chymotrypsin-type serine protease. Caldecrin is synthesized as proform and secreted from the cells. In the course of research project that explore the function of caldecrin, we found the results as follows; 1) caldecrin suppressed bone resorption without its protease activity. The amino acid sequence corresponding to rat caldecrin (aa71-79) is responsible for the suppression of bone resorption by caldecrin. 2) Caldecrin was expressed in the skeletal muscle and its mRNA expression was increased with the progress of muscle differentiation. 3) Caldecrin detected in adult rat brain.The caldecrin gene was constitutively expressed during postnatal days 1-28 in the brain. The caldecrin mRNA was detected in the whole brain, including the olfactory bulb, cerebrum, hippocampus, thalamus and cerebellum.These results indicate that caldecrin is multi-functional protease.