Internal Standard for Clinical Mass Spectrometry

L-Tryptophan-d₅ is the deuterium labeled L-Tryptophan. L-Tryptophan (Tryptophan) is an essential amino acid that is the precursor of serotonin, melatonin, and vitamin B3.

L-Phenylalanine-d₅ is the deuterium labeled L-Phenylalanine. L-Phenylalanine ((S)-2-Amino-3-phenylpropionic acid) is an essential amino acid isolated from Escherichia coli. L-Phenylalanine is a α2δ subunit of voltage-dependent Ca+ channels antagonist with a K_i of 980 nM. L-phenylalanine is a competitive antagonist for the glycine- and glutamate-binding sites of N-methyl-D-aspartate receptors (NMDARs) (KB of 573 μM ) and non-NMDARs, respectively. L-Phenylalanine is widely used in the production of food flavors and pharmaceuticals.

Cholesterol-d₇ is the deuterium labeled Cholesterol. Cholesterol is the major sterol in mammals. It is making up 20-25% of structural component of the plasma membrane. Plasma membranes are highly permeable to water but relatively impermeable to ions and protons. Cholesterol plays an important role in determining the fluidity and permeability characteristics of the membrane as well as the function of both the transporters and signaling proteins. Cholesterol is also an endogenous estrogen-related receptor α (ERRα) agonist.

L-Arginine-¹³C₆,¹⁵N₄ (hydrochloride) is the ¹³C- and ¹⁵N-labeled L-Arginine hydrochloride. L-Arginine hydrochloride ((S)-(+)-Arginine hydrochloride) is the nitrogen donor for synthesis of nitric oxide, a potent vasodilator that is deficient during times of sickle cell crisis.

L-Leucine-d₃ is the deuterium labeled L-Leucine. L-Leucine is an essential branched-chain amino acid (BCAA), which activates the mTOR signaling pathway.

Choline-¹³C₂ chloride is the ¹³C-labeled Choline chloride (HY-B1337). Choline chloride is an orally active methylxanthine derivative. Choline chloride exhibits weak antihistaminic and anticholinergic activities and potentiates the effects of histamine and acetylcholine. Choline chloride relaxes bronchial smooth muscle, dilates coronary and peripheral blood vessels, increases urine output and electrolyte excretion, stimulates locomotor activity in the central nervous system, and induces transient hypotension following a pressor phase. Choline chloride modulates sleep architecture by increasing wakefulness time and reducing slow-wave sleep, without altering the frequency or severity of nocturnal hypoxemia, apnea, or hypopnea events. Choline chloride is used in studies of bronchospasm, nocturnal asthma, and chronic asthma.

Deuruxolitinib (CTP-543; Ruxolitinib-d₈) is a deuterated analog of Ruxolitinib (HY-50856) and an orally active, selective inhibitor of JAK1 and JAK2. Deuruxolitinib blocks Janus kinase-mediated cytokine receptor signaling and proinflammatory cytokine gene expression. Deuruxolitinib is primarily metabolized in the liver via CYP2C9. Deuruxolitinib promotes scalp hair regrowth in severe chronic alopecia areata. Deuruxolitinib is used in alopecia areata-related research.

Rosuvastatin-d₃ sodium is the deuterated-labeled Rosuvastatin Sodium (HY-17504B). Rosuvastatin Sodium is a competitive HMG-CoA reductase (HMGCR) inhibitor, with an IC₅₀ of 11 nM. Rosuvastatin Sodium potently blocks hERG current with an IC₅₀ of 195 nM. Rosuvastatin Sodium reduces the expression of the mature hERG and the interaction of heat shock protein 70 (Hsp70) with the hERG protein. Rosuvastatin Sodium effectively lowers low-density lipoprotein (LDL) cholesterol, triglycerides, and C-reactive protein levels.

Water-¹⁸O is the ¹⁸O-labeled Water.

Sorafenib-d₃ (Donafenib) is the deuterated-labeled Sorafenib (HY-10201). Sorafenib (Bay 43-9006) is a potent oral active multikinase inhibitor. Sorafenib blocks autophosphorylation and activity of receptor tyrosine kinases (VEGFR-2, VEGFR-3) and RAF family kinases, thereby suppressing the RAF/MEK/ERK and PI3K/Akt pathways, inhibiting STAT3 phosphorylation, and selectively inhibiting the MAPK pathway in cancer cells. Sorafenib induces cell cycle arrest, autophagy, apoptosis, and PARP cleavage, reduces Bcl-2, Bcl-XL, cyclin D1 levels, and activates Bak and Bax. Sorafenib inhibits tumor growth and metastasis in mouse and rat models. Sorafenib can be used for cancer research, such as colon, breast, non-small-cell lung cancer (NSCLC), ovarian, pancreatic, melanoma, colorectal and hepatocellular carcinoma.

L-Glutamine-¹⁵N₂ is the ¹⁵N-labeled L-Glutamine (HY-N0390). L-Glutamine is an orally active nutritional agent and cellular metabolism regulator. L-Glutamine is taken up in a Na⁺-dependent manner and targets multiple key molecules including glutaminase, mTORC1, NF-κB, STAT-3 and HIF-1α. L-Glutamine enhances glutaminolytic catabolism, drives the conversion of glutamate to α-ketoglutarate, thereby regulating gene expression, integrating metabolic signals, mediating glutamine flux and maintaining redox homeostasis. L-Glutamine also promotes cell proliferation, osteogenic differentiation and fracture healing, exerts neuroprotective and cardioprotective effects, and inhibits osteoarthritis. L-Glutamine can be applied to research related to osteoporosis, osteoarthritis, ischemic stroke and acute cantharidin-induced cardiotoxicity.

Adenosine-¹³C₅ is the ¹³C labeled Adenosine. Adenosine (Adenine riboside), a ubiquitous endogenous autacoid, acts through the enrollment of four G protein-coupled receptors: A1, A2A, A2B, and A3. Adenosine affects almost all aspects of cellular physiology, including neuronal activity, vascular function, platelet aggregation, and blood cell regulation.

S-Adenosyl-L-methionine-d₃ (S-Adenosyl methionine-d₃) is the deuterated product of S-Adenosyl-L-methionine (HY-B0617). S-Adenosyl-L-methionine (S-Adenosyl methionine) is an orally active methyl group donor. S-Adenosyl-L-methionine is a dietary supplement with potent antidepressant effects. S-Adenosyl-L-methionine also has anti‑proliferative, pro‑apoptotic and anti‑metastatic roles in cancers. S-Adenosyl-L-methionine has the potential for, cancer, liver disease and osteoarthritis research.

L-Arginine-¹³C₆ (hydrochloride) is the ¹³C-labeled L-Arginine hydrochloride. L-Arginine hydrochloride ((S)-(+)-Arginine hydrochloride) is the nitrogen donor for synthesis of nitric oxide, a potent vasodilator that is deficient during times of sickle cell crisis.

2-Ketoglutaric acid-¹³C₅ (Alpha-Ketoglutaric acid-¹³C₅) is a ¹³C labeled 2-Ketoglutaric acid (HY-W013636). 2-Ketoglutaric acid (Alpha-Ketoglutaric acid) is an intermediate in the production of ATP or GTP in the Krebs cycle. 2-Ketoglutaric acid also acts as the major carbon skeleton for nitrogen-assimilatory reactions. 2-Ketoglutaric acid is a reversible inhibitor of tyrosinase (IC₅₀=15 mM).

3-Indoleacetic acid-d₅ (Indole-3-acetic acid-d₅) is the deuterated-labeled 3-Indoleacetic acid (HY-18569). 3-Indoleacetic acid is is an IAA hormone and growth regulator that can promote plant nutritional growth through processes such as cell expansion, differentiation, morphogenesis, and organogenesis.

γ-Aminobutyric acid-d₆ is the deuterium labeled γ-Aminobutyric acid. γ-Aminobutyric acid (4-Aminobutyric acid) is a major inhibitory neurotransmitter in the adult mammalian brain, binding to the ionotropic GABA receptors (GABAA receptors) and metabotropic receptors (GABAB receptors).

Ammonium chloride-¹⁵N is the ¹⁵N labeled Ammonium chloride (HY-Y1269). Ammonium chloride, as a heteropolar compound with pH value regulation, can cause intracellular alkalization and metabolic acidosis thus effecting enzymatic activity and influencing the process of biological system. Ammonium chloride is an autophagy inhibitor. Ammonium chloride is also a lysosome inhibitor.

L-Serine-¹³C₃ is the ¹³C-labeled L-Serine. L-Serine ((-)-Serine; (S)-Serine), one of the so-called non-essential amino acids, plays a central role in cellular proliferation.

Nicotinamide-d₄ is the deuterium labeled Nicotinamide. Nicotinamide is a form of vitamin B3 that plays essential roles in cell physiology through facilitating NAD+ redox homeostasis and providing NAD+ as a substrate to a class of enzymes that catalyze non-redox reactions. Nicotinamide is an inhibitor of SIRT1.