KM71H Chemically Competent Cell

KM71H Chemically Competent Cell

The KM71H strain is a Pichia pastoris strain developed by Invitrogen specifically for recombinant protein expression. KM71H can express the HIS4 gene and cannot be used for screening positive colonies of successful recombinants on a nutrient-deficient medium. Pichia pastoris expression plasmids such as pPICZ A, B, C, pPICZα A, B, C, etc., which carry the Zeocin resistance gene, can be screened with 100 μg/ml Zeocin or bleomycin hydrochloride. The phenotype of KM71H Pichia pastoris is MutS, Arg+. Arg+ indicates that the parent strain of KM71H has a mutation in the arginine succinate lyase gene (arg4), and the introduction of the wild-type ARG4 gene at the AOX1 gene locus simultaneously disrupted the AOX1 gene, resulting in the MutS phenotype; MutS indicates that the AOX1 gene function of KM71H is disrupted (Pichia pastoris is a methanol-nutrient yeast that can use methanol as the sole carbon source. The first step of methanol metabolism is that alcohol oxidase uses oxygen molecules to oxidize methanol to formaldehyde. There are two genes in Pichia pastoris that encode alcohol oxidase: AOX1 and AOX2. In wild-type Pichia pastoris, most of the alcohol oxidase is the product of the AOX1 gene, and methanol can induce the expression of the AOX1 gene. The AOX1 protein product can account for more than 30% of the soluble protein in the cell. Many Pichia pastoris expression plasmids use the AOX1 expression cassette for the expression of exogenous genes. If Pichia pastoris contains a functional AOX1 gene, it is called the Mut+ type; AOX2 is a homologous gene of AOX1 (97% homology). When the AOX1 gene is missing or loses its function, the AOX2 gene will play a role, generating a MutS mutant strain. However, the ability of AOX2 to oxidize methanol is much weaker than that of AOX1, resulting in a decrease in the cell's ability to metabolize methanol and slow growth in methanol medium. For a specific protein, it is difficult to predict whether Mut+ or MutS should be selected as the host for protein expression. Although Mut+ type yeast transcribes more mRNA, excessive mRNA does not necessarily produce active proteins; although MutS type yeast grows slowly and transcribes less mRNA than Mut+, it may be more conducive to the formation of the correct protein conformation and the production of active proteins). KM71H chemically competent cells are made by a special process and can be stored at -80°C for 12 months. The transformation efficiency of linearized pPICZ A plasmid (3.3 kb, ZeocinR in E. coli/Pichia pastoris) was detected to be >10⁴ cfu/μg DNA.

1. This product is for scientific research use only. Please do not use it for medical, clinical diagnosis or treatment, food and cosmetics, etc. Please not store it in a general residential area.

2. For your safety and health, please wear a lab coat and disposable gloves and masks when operating.

3. The experimental can be affected by a variety of factors, and the relevant treatment is limited to the product itself, and does not involve other compensation.