Recombinant production of medium- to large-sized peptides in Escherichia coli using a cleavable self-aggregating tag

Table 2 Summary of peptide production and purification schemes

Target peptide	Final yield of respective schemes (μg/mg wet cell pellet)^a
Target peptide	Scheme 1A	Scheme 1B	Scheme 2
	Step 1: Expression of fusion protein Peptide-Intein-ELK16	Step 1: Expression of fusion protein Peptide-Intein-ELK16	Step 1: Expression of fusion protein Trx-Peptide-Intein-ELK16
	Step 2: Intein-mediated cleavage	Step 2: Intein-mediated cleavage	Step 2: Intein-mediated cleavage
	Step 3: RP-HPLC	Step 3: Refolding	Step 3: Enterokinase cleavage
		Step 4: RP-HPLC	Step 4: RP-HPLC
GLP-1	0.8 (20.8 %)^b	–	1.1 (25.2 %)
BNP	No expression	–	1.8 (42.2 %)
Ex-4	No expression	–	0.3 (26.5 %)
IGF-1α	Insoluble	0.3 (3.6 %)	Unwanted enterokinase site
CCL5	Insoluble	0.1 (1.2 %)	Insoluble
SDF-1α	Insoluble	0.4 (5.8 %)	0.2 (2.0 %)
Leptin	Insoluble	0.6 (3.4 %)	Insoluble

^aYield of target peptide after fine purification by RP-HPLC from LB culture with wet cell weight of 2.66 ± 0.99 mg/mL, quantified by the Pierce® bicinchoninic acid (BCA) assay kit
^bThe final recovery after RP-HPLC purification listed in parentheses and calculated by dividing the product peptide yield by the theoretical value from aggregate yield in Table 1

ISSN: 1475-2859