Peptidyl prolyl cis/trans isomerases (PPIases) catalyze the slow cis/trans isomeraization of proline peptide (Xaa-Pro) bonds in oligopeptides and accelerates slow, rate-limiting steps in the folding of several proteins. We studied the characterization of Cyclophilin A (bCyp A) isolated from Bombyx mori . The cDNA of bCyp A is 947 bp. There is a 5´-untranslated region of 91 nucleotides followed by an initiating ATG codon. The TAA termination codon occurs at nucleotide 588. Thus translation of the sequence from nucleotides 91 to 588 would produce a protein of 166 amino acids with a calculated molecular mass of 18.2kDa. The 'AATAAA' consensus polyadenylation signal and poly A tail are present in the 3´-untranslated region. To analysis of PPIase activity, we expressed the bCyp A protein in Sf9 cell by using baculovirus expression vector system (BEVS). SDS-PAGE and Western blot analysis showed that the molecular weights of intracelluar expressed protein was approximately 28.2 kDa. The PPIase activity assay was monitored by proteolytic cleavage of the chromophore p-nitroanilide byα-chymotrypsin. As substrate the synthetic tetrapeptide succinyl-Ala-Ala- Pro-Phe-p-nitroanilide was used.

더덕 뿌리에서 유래한 EST cDNA library로부터 cyclophilin 유전자와 높은 상동성을 나타내 는 full clone cDNA를 얻었다. 더덕의 cyclophilin, ClCyP1은 747 bp의 cDNA로 174개의 아미노산을 코딩하는 525 bp의 ORF를 가지고 있다. ClCyP1의 아미노산 서열을 분석한 결과, 기존에 보고된 식물들의 cytosolic cyclophilin들과 높은 상동성을 나타내었으며, 여러 식물의 cytosolic CyP의 공통적인 특징인 7개의 아미노산 잔기(KSGKPLH)를 가지고 있었다. RT-PCR분석 결과, 더덕의 ClCyP1은 식물의 조직 전체에서 발현되며, 저온, 고온, 그리고 염 스트레스에 대해 그 발현량이 증가하였다.