Characterization and determination of titratable groups of proteins by linearization of titration curves. II. Application to lysozyme

Journal Article · Thu Jul 01 00:00:00 EDT 1982 · Anal. Biochem.; (United States)

DOI:https://doi.org/10.1016/0003-2697(82)90441-9· OSTI ID:5581296

Godinho, O E.S. ^[1]; Aleixo, L M; Alves, J P.H.

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1. Univ. Estadual de Campinas, Brazil

The potentiometric acid-base titration curves of fully protonated lysozyme at ionic strenghts of 0.10 and 1.0 M has been performed. The stoichiometry and the pK/sub a/ values of each titratable group have been determined through the linearization of titration curves. Two types of carboxylic groups with pK/sub a/ values of 3.76 and 5.02, the imidazole group with pK/sub a/ 7.37 and the amino group with pK/sub a/ 9.63, have been identified at an ionic strength of 0.10 M at 25.0/sup 0/C. The number of titratable groups found per mole of protein has been 5.12 and 5.60 for the two types of carboxylic groups, 1.13 for the imidazole group, and 3.19 for the amino groups. The endpoint of the titration of the protein obtained by this method accords quite well with the endpoint obtained by the use of Gran function applied to the excess of strong base.

• OSTI ID: 5581296
• Journal Information: Anal. Biochem.; (United States), Vol. 123:2
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
LYSOZYME
CHEMICAL REACTION KINETICS
MOLECULAR STRUCTURE
AMINO ACIDS
CARBOXYLIC ACIDS
IMIDAZOLES
STOICHIOMETRY
TITRATION
AZOLES
ENZYMES
GLYCOSYL HYDROLASES
HETEROCYCLIC COMPOUNDS
HYDROLASES
KINETICS
O-GLYCOSYL HYDROLASES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
REACTION KINETICS
400102* - Chemical & Spectral Procedures