title: Interference of salts used on aqueous two-phase systems on the quantification of total proteins.
abstract: In this study the interference of potassium phosphate, sodium citrate, sodium chloride and sodium nitrate salts on protein quantification by Bradford's method was assessed. Potassium phosphate and sodium citrate salts are commonly used in aqueous two-phase systems for enzyme purification. Results showed that the presence of potassium phosphate and sodium citrate salts increase the absorbance of the samples, when compared with the samples without any salt. The increase in absorptivity of the solution induces errors on protein quantification, which are propagated to the calculations of specific enzyme activity and consequently on purification factor. The presence of sodium chloride and sodium nitrate practically did not affect the absorbance of inulinase, probably the metals present in the enzyme extract did not interact with the added salts.
authors.affiliation: Universidade Regional Integrada do Alto Uruguai e das Missões, Campus de Erechim, Departamento de Engenharia de Alimentos, Av. 7 de Setembro, 1621, Erechim, RS 99700-000, Brazil; Universidade Federal da Fronteira Sul, Campus de Erechim, ERS 135 km 72 n°200, Caixa Postal 764, Erechim, RS 99700-970, Brazil.
authors.forename: Simone Maria
authors.initials: SM
authors.lastname: Golunski
authors.affiliation: Universidade Federal do Rio Grande, Escola de Química e Alimentos, PO Box 474, Rio Grande, RS 96201-900, Brazil.
authors.forename: Luisa
authors.initials: L
authors.lastname: Sala
authors.affiliation: Universidade Regional Integrada do Alto Uruguai e das Missões, Campus de Erechim, Departamento de Engenharia de Alimentos, Av. 7 de Setembro, 1621, Erechim, RS 99700-000, Brazil.
authors.forename: Marceli Fernandes
authors.initials: MF
authors.lastname: Silva
authors.affiliation: Universidade Regional Integrada do Alto Uruguai e das Missões, Campus de Erechim, Departamento de Engenharia de Alimentos, Av. 7 de Setembro, 1621, Erechim, RS 99700-000, Brazil.
authors.forename: Rogério Marcos
authors.initials: RM
authors.lastname: Dallago
authors.affiliation: Universidade Federal da Fronteira Sul, Campus de Erechim, ERS 135 km 72 n°200, Caixa Postal 764, Erechim, RS 99700-970, Brazil.
authors.forename: Jéssica
authors.initials: J
authors.lastname: Mulinari
authors.affiliation: Universidade Federal da Fronteira Sul, Campus de Erechim, ERS 135 km 72 n°200, Caixa Postal 764, Erechim, RS 99700-970, Brazil.
authors.forename: Altemir José
authors.initials: AJ
authors.lastname: Mossi
authors.affiliation: Universidade Federal do Rio Grande do Sul, Instituto de Ciência e Tecnologia de Alimentos, Rio Grande, RS 96201-900, Brazil.
authors.forename: Adriano
authors.initials: A
authors.lastname: Brandelli
authors.affiliation: Universidade Federal do Rio Grande, Escola de Química e Alimentos, PO Box 474, Rio Grande, RS 96201-900, Brazil.
authors.forename: Susana Juliano
authors.initials: SJ
authors.lastname: Kalil
authors.affiliation: Universidade Federal de Santa Catarina, Departamento de Engenharia Química e Engenharia de Alimentos, PO Box 476, Florianópolis, SC 88040-900, Brazil.
authors.forename: Marco
authors.initials: M
authors.lastname: Di Luccio
authors.affiliation: Universidade Federal da Fronteira Sul, Campus de Erechim, ERS 135 km 72 n°200, Caixa Postal 764, Erechim, RS 99700-970, Brazil. Electronic address: helentreichel@gmail.com.
authors.forename: Helen
authors.initials: H
authors.lastname: Treichel
mesh_terms: D002951:Citrates / Q000737:chemistry; D009566:Nitrates / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D012492:Salts / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D000077559:Sodium Citrate; D012995:Solubility; D014867:Water / Q000737:chemistry*
chemical_list: D002951:Citrates; D009566:Nitrates; D010710:Phosphates; D017680:Potassium Compounds; D011506:Proteins; D012492:Salts; D014867:Water; D000077559:Sodium Citrate; D012965:Sodium Chloride; C031618:sodium nitrate; C013216:potassium phosphate
keywords: Bradford; Inulinase; Keratinase