Preparation Instructions: This product is soluble in $\pu{1 M} \ \ce{ HCl}$ ($\pu{100 mg/ml}$), with heating. The solubility in water ($\pu{25 ^\circ C}$) is $\pu{0.45 mg/ml}$ in the pH range $3.2-7.5$ (Ref.1). At $\mathrm{pH}$$1.8$, the solubility is $\pu{2.0 mg/ml}$; at $\mathrm{pH}$$9.5$, the solubility is $\pu{1.4 mg/ml}$; and at $\mathrm{pH}$$10$, the solubility is $\pu{3.8 mg/ml}$.
The above claims can be justified by the study of the solubility of tyrosine in the acidic and basic conditions (Ref.2), the summery of which states that:
Measurements have been made of the solubility at $\pu{25 ^\circ C}$ of tyrosine in hydrochloric acid and in sodium hydroxide solutions varying from $0.001$ to $\pu{0.05 M}$, and also in distilled water. The $\mathrm{pH}$ of the saturated solutions was measured with the hydrogen electrode. The following values for the ionization constants of tyrosine have been obtained from the measurements: $k_\mathrm{b} = 1.57 \times 10^{–12}$, $k_\mathrm{a1} = 7.8 \times 10^{–10}$, $k_\mathrm{a2} = 8.5 \times 10^{–11}$. The changes in solubility with $\mathrm{pH}$ can be satisfactorily explained by the use of these ionization constants.
According to plot of solubility versus $\mathrm{pH}$ of their results, it was concluded that the highest solubility of tyrosine can be achieved in the $\mathrm{pH}$ range of $1-2$ or in the $\mathrm{pH}$ range of $9-10$. For example, the concentration of tyrosine in $\pu{0.05 M}$$\ce{HCl}$ is found to be $\pu{0.0165 M}$ with the $\mathrm{pH}$ of solution being $1.450$. And also, the concentration of tyrosine in $\pu{0.0498 M}$$\ce{NaOH}$ is found to be $\pu{0.0358 M}$ with the $\mathrm{pH}$ of solution being $9.953$. The least solubility of tyrosine is shown to be with in the $\mathrm{pH}$ range of $3-8.5$ (Ref.2).
Note: The extrapolation of the acidic side of above graph has shown the solubility increases up to about $\pu{0.04 M}$ at $\mathrm{pH} = 1$ (Ref.2).
References:
T. A. Brown, In Molecular Biology: LabFax; 1st Edition; Bios Scientific Publishers: Oxford, England, 1991, p. 29 (ISBN: 1‐872748‐00‐7).
David I. Hitchcock, "The solubility of tyrosine in the acid and in alkali," Journal of General Physiology1924, 6(6), 747–757 (https://doi.org/10.1085/jgp.6.6.747)(PDF).
Preparation Instructions: This product is soluble in $\pu{1 M} \ \ce{ HCl}$ ($\pu{100 mg/ml}$), with heating. The solubility in water ($\pu{25 ^\circ C}$) is $\pu{0.45 mg/ml}$ in the pH range $3.2-7.5$ (Ref.1). At $\mathrm{pH}$$1.8$, the solubility is $\pu{2.0 mg/ml}$; at $\mathrm{pH}$$9.5$, the solubility is $\pu{1.4 mg/ml}$; and at $\mathrm{pH}$$10$, the solubility is $\pu{3.8 mg/ml}$.
The above claims can be justified by the study of the solubility of tyrosine in the acidic and basic conditions (Ref.2), the summery of which states that:
Measurements have been made of the solubility at $\pu{25 ^\circ C}$ of tyrosine in hydrochloric acid and in sodium hydroxide solutions varying from $0.001$ to $\pu{0.05 M}$, and also in distilled water. The $\mathrm{pH}$ of the saturated solutions was measured with the hydrogen electrode. The following values for the ionization constants of tyrosine have been obtained from the measurements: $k_\mathrm{b} = 1.57 \times 10^{–12}$, $k_\mathrm{a1} = 7.8 \times 10^{–10}$, $k_\mathrm{a2} = 8.5 \times 10^{–11}$. The changes in solubility with $\mathrm{pH}$ can be satisfactorily explained by the use of these ionization constants.
According to plot of solubility versus $\mathrm{pH}$ of their results, it was concluded that the highest solubility of tyrosine can be achieved in the $\mathrm{pH}$ range of $1-2$ or in the $\mathrm{pH}$ range of $9-10$. For example, the concentration of tyrosine in $\pu{0.05 M}$$\ce{HCl}$ is found to be $\pu{0.0165 M}$ with the $\mathrm{pH}$ of solution being $1.450$. And also, the concentration of tyrosine in $\pu{0.0498 M}$$\ce{NaOH}$ is found to be $\pu{0.0358 M}$ with the $\mathrm{pH}$ of solution being $9.953$. The least solubility of tyrosine is shown to be with in the $\mathrm{pH}$ range of $3-8.5$ (Ref.2).
Note: The extrapolation of the acidic side of above graph has shown the solubility increases up to about $\pu{0.04 M}$ at $\mathrm{pH} = 1$ (Ref.2).
References:
T. A. Brown, In Molecular Biology: LabFax; 1st Edition; Bios Scientific Publishers: Oxford, England, 1991, p. 29 (ISBN: 1‐872748‐00‐7).
David I. Hitchcock, "The solubility of tyrosine in the acid and in alkali," Journal of General Physiology1924, 6(6), 747–757 (https://doi.org/10.1085/jgp.6.6.747)(PDF).
@Hans: I did not concentrate on solubility with temperature since it wasnt a concern according to the question. Nevertheless, solubility decreases with the decreasing temperature as rule of thumb. Since solubility of tyrosine is highly depend on its ionization (total positive or negative charge by acid or base, respectively), difference in solubility might not be too big of a deal (More
According to Product Information of Sigma-Aldrich for L-Tyrosine, the solubility is $\mathrm{pH}$-dependent:
The above claims can be justified by the study of the solubility of tyrosine in the acidic and basic conditions (Ref.2), the summery of which states that:
According to plot of solubility versus $\mathrm{pH}$ of their results, it was concluded that the highest solubility of tyrosine can be achieved in the $\mathrm{pH}$ range of $1-2$ or in the $\mathrm{pH}$ range of $9-10$. For example, the concentration of tyrosine in $\pu{0.05 M}$ $\ce{HCl}$ is found to be $\pu{0.0165 M}$ with the $\mathrm{pH}$ of solution being $1.450$. And also, the concentration of tyrosine in $\pu{0.0498 M}$ $\ce{NaOH}$ is found to be $\pu{0.0358 M}$ with the $\mathrm{pH}$ of solution being $9.953$. The least solubility of tyrosine is shown to be with in the $\mathrm{pH}$ range of $3-8.5$ (Ref.2).
Note: The extrapolation of the acidic side of above graph has shown the solubility increases up to about $\pu{0.04 M}$ at $\mathrm{pH} = 1$ (Ref.2).
References:
According to Product Information of Sigma-Aldrich for L-Tyrosine, the solubility is $\mathrm{pH}$-dependent:
The above claims can be justified by the study of the solubility of tyrosine in the acidic and basic conditions (Ref.2), the summery of which states that:
According to plot of solubility versus $\mathrm{pH}$ of their results, it was concluded that the highest solubility of tyrosine can be achieved in the $\mathrm{pH}$ range of $1-2$ or in the $\mathrm{pH}$ range of $9-10$. For example, the concentration of tyrosine in $\pu{0.05 M}$ $\ce{HCl}$ is found to be $\pu{0.0165 M}$ with the $\mathrm{pH}$ of solution being $1.450$. And also, the concentration of tyrosine in $\pu{0.0498 M}$ $\ce{NaOH}$ is found to be $\pu{0.0358 M}$ with the $\mathrm{pH}$ of solution being $9.953$. The least solubility of tyrosine is shown to be with in the $\mathrm{pH}$ range of $3-8.5$ (Ref.2).
Note: The extrapolation of the acidic side of above graph has shown the solubility increases up to about $\pu{0.04 M}$ at $\mathrm{pH} = 1$ (Ref.2).
References:
More
VOTE
VOTE
VOTE
VOTE
VOTE