Abstract: The process for producing the albumin preparation of the present invention comprises treating an aqueous albumin solution with an anion exchanger and a cation exchanger and subjecting the solution to heat treatment wherein a polyacrylamide type carrier having a cation exchange group is used as a cation exchanger. By using a polyacrylamide type carrier as a cation exchanger, the polymerization caused by the contaminating proteins can be suppressed, and a highly purified albumin preparation can be obtained.

Abstract: A method for preparing foreign protein in yeast using an expression recombinant DNA comprising DNA encoding the serum albumin signal peptide adjacent to DNA encoding the foreign protein is disclosed.

Abstract: The present invention is to provide an optical switch that enables size reduction of the switch, facilitation of positioning of an optical fiber, simplification of the structure of an actuator, improvements in assembly operability and reliability of the apparatus, facilitation of an application to a multi-core structure, facilitation of alignment of a plurality of optical fibers, and the like. A displacement stage 5 for mounting a single optical fiber 2 thereon, an elevating stage 20 for mounting a plurality of second optical fibers 3 thereon in a lateral line, and a linear encoder 14 for controlling a coil motor 9 are disposed in a case 1. The displacement stage 5 is displaced by the coil motor in the horizontally lateral direction. Simultaneously, the elevating stage 20 is moved upward by the actuator 19, and the first optical fiber 2 is caused to abut against an arbitrary second optical fiber to selectively couple them, thereby switching the optical path of an optical fiber.

Abstract: Novel signal peptides capable of functioning in yeasts have the amino acid sequence:Met-A.sub.1 -A.sub.2 -X-B-C-D-E-Fwherein A.sub.1 is a peptide chain composed of 1-3 amino acids each selected from the group consisting of Arg, Ser, Lys and His, A.sub.2 is a peptide chain composed of 1-3 amino acids, X is a peptide chain composed of 8-10 hydrophobic amino acids, B is Pro or Ser, C is Gly or Pro, D Cys, Ala, Leu, Ser, Thr and Val, E is Trp or Gln and F is Ala or Gly. DNA sequences coding for these signal peptides can be used for the secretory expression of heterologous proteins in yeasts.