Abstract: The present invention is directed to a transformant comprising the following expression units in a co-expressible state:an expression unit containing a gene coding for a receptor protein ERD2 from yeast or analog thereof which is capable of binding to a protein localizing in endoplasmic reticulum and having a signal for staying therein;an expression unit containing a gene coding for said protein localizing in endoplasmic reticulum; andan expression unit containing a foreign gene coding for a polypeptide which is a subject of function of said protein localizing in endoplasmic reticulum, andto a transformant comprising, in a co-expressible state, a fusion gene which is composed of a DNA fragment coding for a human serum albumin prepro-sequence and a foreign gene coding for a useful polypeptide. The present invention is also directed to a process for producing said polypeptide by co-expressing said genes in said transformant such that the polypeptide is predominantly secreted out of the transformant cell.

Abstract: A yeast PPIase characterized by possessing following properties: (1) acting on and isomerizing the bond X.sub.aa -Pro (wherein X.sub.aa stands for any amino acid and Pro stands for L-proline), (2) exhibiting a single molecular weight of about 17,000 daltons in the sodium dodecyl sulfate-polyacrylamide concentration gradient gel electrophoresis, (3) exhibiting a single isoelectric point of about 6.2 in the isoelectric focusing, and (4) inhibited by CsA;an E. coli PPIase-.beta. characterized by possessing the following properties: (1) acting on and isomerizing the bond X.sub.aa -Pro (wherein X.sub.aa stands for any amino acid and Pro for L-proline), (2) exhibiting a single molecular weight of about 20,000 daltons in the sodium dodecyl sulfate-polyacrylamide concentration gradient gel electrophoresis, (3) exhibiting a single isoelectric point of about 5.0 in the isoelectric focusing, and (4) no being inhibited by CsA;an E. coli PPIase-.alpha.

Abstract: A yeast PPIase characterized by possessing the following properties: (1) acting on and isomerizing the bond X.sub.aa -Pro (wherein X.sub.aa stands for any amino acid and Pro stands for L-proline), (2) exhibiting a single molecular weight of about 17,000 daltons in the sodium dodecyl sulfate-polyacrylamide concentration gradient gel electrophoresis, (3) exhibiting a single isoelectric point of about 6.2 in the isoelectric focusing, and (4) inhibited by CsA;an E. coli PPIase-.beta. characterized by possessing the following properties: (1) acting on and isomerizing the bond X.sub.aa -Pro (wherein X.sub.aa stands for any amino acid and Pro for L-proline), (2) exhibiting a single molecular weight of about 20,000 daltons in the sodium dodecyl sulfate-polyacrylamide concentration gradient gel electrophoresis, (3) exhibiting a single isoelectric point of about 5.0 in the isoelectric focusing, and (4) no being inhibited by CsA;an E. coli PPIase-.alpha.