Unit Converter
Alanine (Ala)
ALANINE (Ala)(L-Alanine - Plasma Amino Acid)
Synonyms
- L-Alanine
- Ala
- 2-Aminopropanoic acid
- α-Alanine
- Proteinogenic amino acid (non-essential)
Units of Measurement
µmol/L, mg/L, mg/dL, mg/100mL, mg%, µg/mL
Description
Alanine is a non-essential, glucogenic amino acid synthesized primarily from pyruvate. It plays a central role in:
- Amino acid metabolism
- Glucose–alanine cycle
- Nitrogen transport
- Liver gluconeogenesis
In blood, alanine reflects protein turnover, muscle metabolism, and hepatic gluconeogenesis.
It is commonly measured as part of:
- Plasma amino acid profiling
- Screening for metabolic disorders
- Evaluation of nutritional status
- Research in diabetes, obesity, NAFLD
Physiological Role
1) Glucose–Alanine Cycle
Alanine carries amino groups from muscle to liver for safe disposal via the urea cycle.
Liver converts alanine → pyruvate → glucose → returned to muscle.
2) Protein Synthesis
Alanine is incorporated into proteins; it is one of the most frequently occurring amino acids in human proteins.
3) Energy Metabolism
A key substrate for:
- Gluconeogenesis
- Transamination reactions
- Nitrogen transport
4) Link with Insulin Resistance
High alanine levels correlate with:
- Increased gluconeogenesis
- Insulin resistance
- Type 2 diabetes risk
(Shown in recent metabolomic studies.)
Clinical Significance
Elevated Alanine (Hyperalaninemia)
Seen in:
- Maple Syrup Urine Disease (MSUD)
- Pyruvate dehydrogenase deficiency
- Hyperalimentation / TPN infusion
- Liver disease (enhanced alanine release)
- Muscle catabolism
- Insulin resistance / prediabetes
- Metabolic acidosis
- Ketogenic diet or starvation states
Mild elevations can occur post-meal due to amino acid absorption.
Low Alanine
Occurs in:
- Malnutrition
- Severe liver failure
- Chronic illness / catabolic states
- Inherited amino-acid disorders
- Post-dialysis states
- Very low protein intake
Reference Intervals
Plasma / Serum Alanine (Fasting)
- 230 – 510 µmol/L
- ≈ 20 – 45 mg/L
Pediatric ranges vary slightly; typical values:
- Infants: 180 – 450 µmol/L
- Children: 200 – 480 µmol/L
(Ranges may vary by analytical method: LC-MS/MS, HPLC.)
Interpretation Notes
- Always interpret alanine values fasting, as post-prandial levels increase.
- Part of the alanine–pyruvate–glucose axis → elevated levels often parallel increased ALT (but unrelated analytically).
- Inborn errors show dramatic elevations (MSUD, pyruvate metabolism defects).
- In NAFLD and metabolic syndrome, alanine elevation reflects increased gluconeogenic flux.
Unit Meanings
| Unit | Meaning |
| µmol/L | micromole per liter |
| mg/L | milligram per liter |
| mg/dL | milligram per deciliter |
| mg/100mL | equal to mg% |
| mg% | milligram per 100mL |
| µg/mL | microgram per milliliter |
Clinical Pearls
- Fasting levels reflect true metabolic status.
- Elevated alanine often parallels high ALT in metabolic disease (due to shared pyruvate metabolism).
- An unusually high alanine level suggests mitochondrial disorders or branched-chain amino acid disorders.
- In diabetes, alanine is a marker for hepatic insulin resistance.
- In TPN, alanine rises quickly due to infusion amino acid composition.
Interesting Fact
Alanine was discovered in 1850 in silk protein hydrolysates — it became a key molecule in understanding amino acid metabolism and the glucose–alanine shuttle in muscle physiology.
References
- Tietz Clinical Chemistry and Molecular Diagnostics, 8th Edition - Amino Acid, Metabolites Chapter.
- Mayo Clinic Laboratories - Plasma Amino Acid Profile.
- IFCC - Reference intervals for plasma amino acids.
- ARUP Consult - Inborn Errors of Metabolism Reference Tables.
- NIH / MedlinePlus - Amino Acids Overview.
- Felig P. “The Glucose–Alanine Cycle” - Metabolism & Physiology Journal.
- PubChem - Alanine molecular data.