Biomedical Engineering Reference
In-Depth Information
Table 1.7.
K
JELDAHL
factors
Sample
Species
N (%)
Factor
F
Protein
Serum albumin
Man
15.95
6.20
Serum albumin
Cattle
16.07
6.22
Ovalbumin
Chicken
15.76
6.34
Casein
Cattle
15.63
6.39
Hemoglobin
Pig
16.80
5.95
Histones
Cattle
18.00
5.55
Gliadin
Wheat
17.66
5.66
Legumin
Pea
16.04
5.54
Seed
Roe
17.15
5.83
Wheat
17.15
5.83
Rice
16.80
5.95
Beans, peas
16.00
6.25
Animal
material
Egg
Chicken
16.00
6.25
Meat
Cattle
16.00
6.25
Milk
Cattle
15.67
6.38
References
Jacob S (1965) The determination of nitrogen in biological materials. In:
Glick D (ed.) Methods in biochemical analysis vol. 33, p. 241, Wiley,
New York
Mazor L (1983) Methods in organic analysis, p. 312, Akadémiai Kiadó,
Budapest
1.1.7 UV Photometric Assay of Protein Concentration
The photometric estimation of protein concentration is subject to
some special features: Proteins interact with each other depend-
ing on their concentration and may change their secondary and/or
tertiary structure in a concentration-dependent manner (especially
denaturation in diluted solutions). These changes affect the absorp-
tion of light, i.e., concentration dependence of molar absorption
coefficient
ε
; therefore, the Beer-Lambert law (eq. e) is not valid
over a broad concentration range.
If a compound dissociates in a solvent and one part of the
pair has another absorption than the other (e.g., p-nitrophenol/p-
nitrophenolate), the absorption coefficient changes with dilution.
This should be taken into consideration when different dilutions
ofacompoundarecompared.Theconcentrationofanaqueous
protein solution can be estimated by reading the UV absorption.
The aromatic amino acids (phenylalanine, tryptophan, tyrosine)
