3.2.2.6 gene cd38, eight exons, DNA and amino acid sequence determination and analysis, sequence comparison to the human enzyme, phylogenetic tree, expression in COS-7 cells 3.2.2.6 recombinant expression of bovine CD38/NAD+ glycohydrolase truncated for the first 31 amino acids that encompass the transmembrane and short intracellular domains in Pichia pastoris. The construct comprises a DNA fragment encoding the ecto-domain in the expression plasmid pPICZaA in frame with the yeast alpha-factor secretion signal sequence under the transcriptional control of the AOX1 promoter and keeping its original stop codon 3.2.2.6 the soluble ecto-domain of human CD38 is expressed in Pichia pastoris