As. Pac. J. Mol. Biol. & Biotech., Dec 2000 Vol. 8(2) :123-130

The production of secreted giant catfish growth hormone using Saccharomyces cerevisiae

L. Eurwilaichitr^1,2*, P. Manitchotpisit³, C. Chutrakul¹ and S. Panyim¹

¹Institute of Molecular Biology and Genetics, Mahidol University, Salaya, Nakornpathorn 73170, Thailand; 2Training
Centre for Genetic Engineering and Biotechnology, National Center for Genetic Engineering and Biotechnology at
Institute of Molecular Biology and Genetics, Bangkok, Thailand; 3Microbiology Department,
Rangsit University, Bangkok, Thailand

Received I September 2000 / Accepted 30 November 2000

Abstract.

Giant catfish growth hormone (gcGH) cDNA was expressed under the control of two types of yeast promoters: TEFI, a constitutive promoter and GALI an inducible promoter. Yeast culturing was optimised by using rich buffered medium and high cell density culturing approach. The level of expression when the transformants were grown in BMGYrich medium was approximately 90 mg/l. The strength of the two promoters was not different in expressing gcGH. The gcGH secretion was directed by leader sequence of Saccharomyces cerevisiae a mating type factor. The level of gcGH secretion into medium was about 39-46% of total gcGH produced. The cleavage of a Kex2 recognition site at the N terminal region of the secreted gcGH was accurate, yielding the mature gcGH.

Key Words: Alpha mating factor, GALI promoter, giant catfish growth hormone, Saccharomyces cerevisiae, TEF1 promoter, yeast