κ-Casein from milk

Typical Properties
CAS	9000-71-9
Catalog	ACM9000719-17
Molecular Weight	2061.96 g/mol
Melting Point	280 °C (dec.) (lit.)
Purity	≥70 %
Density	1.26 g/cm3
Solubility	H2O: insoluble, forms a cloudy suspension
Appearance	Powder
Storage	−20 °C
Biological Source	Bovine Milk
Color	white to off-white
Composition	≥70% (PAGE)
EC Number	232-555-1
Grade	Reagent Grade
MDL Number	MFCD00081481
Quality Level	200
Shipping	Ambient
Solvent	Water
Stability	Stable. Combustible. Incompatible with strong oxidizing agents.

Overview

Description

κ-Casein is the smallest and occurs in two main variants, A and B. κ-Caseins surround αs-casein and β-caseins in the micelles. κ-Caseins have no phosphoseryl clusters, but have tetrasaccharide chains attached to threonyl residues 31, 33, 35, and 36 (variant A only). Its N-terminal is hydrophobic, while the other terminal is polar and has no Asp or Glu residues. At pH 6.6, the residues of the C-terminal plus the carbohydrate chains confer a net negative charge of − 16 or − 17. The disulfide form exists in vivo as there is sulfhydryl oxidase activity in raw milk. This molecule is thus highly amphoteric and plays a crucial role in the coagulation of milk catalyzed by chymosin.

Features

·Excellent water resistance
·Excellent fluidity
·Good machinability
·Strong dispersion
·Good biocompatibility

Application

·Quantitative analysis of casein concentration as a standard to evaluate the ability of strains to hydrolyze casein in HM Mozzarella cheese
·Preparation of LPS-deficient cow's milk protein for lymphocyte proliferation assay
·As a reversed-phase high performance liquid chromatography (RP-HPLC) standard for quantitative analysis of kappa-casein concentrations in skim milk samples