PrymaLab

PrymaLab Analytical · In-house laboratory

3705 Music Branch Rd, Ashland, KY 41102 · +1 (606) 465-9063 · prymalab.net

Certificate no.

PL-26-00034

Verification key

U9FXNFGF

Scan or enter both at
prymalab.net/testing/verify

Certificate of Analysis · Lot release

GDF-8 1 mg

Lot PL-2609-034 · Lyophilized powder · Label claim 1 mg/vial

Tested in-house by PrymaLab

In-house analytical result,
not an independent third-party test

Lot / batch number

PL-2609-034

Date made

2026-09-16

Date of analysis

2026-09-18

Date issued

2026-10-03

Retest / expiry

2028-09-16

Units in lot / sampled

250 / 2

Storage

−20 °C, desiccated, dark; avoid freeze–thaw

Certificate type

Lot COA, 2 pages

Compound

GDF-8 (Myostatin)

Recombinant human myostatin, mature homodimer

CAS number

Not assigned

Molecular formula

C₁₁₀₀H₁₆₄₆N₂₉₄O₃₁₆S₂₄ (homodimer; reduced-chain calculation)

Theoretical mass (avg.)

24,814.0 Da (reduced-chain calculation; 24,796.3 Da with the nine disulfides formed)

Structure

Two identical 109-residue chains (UniProt O14793 residues 267–375): DFGLDCDEHSTESRCCRYPLTVDFEAFGWDWIIAPKRYKANYCSGECEFVFLQKYPHTHLVHQANPRGSAGPCCTPTKMSPINMLYFNGKEQIIYGKIPAMVVDRCGCS; disulfide-linked homodimer (TGF-β cystine knot).

Purity · RP-HPLC, area %

99.10%

Specification 99.0% • main peak at 7.06 min

Identity · Observed Mass

24,814.2 Da

Theoretical 24,814.0 Da • +0.2 Da (8 ppm)

Overall conclusion

PASS

Meets every specification for the tests performed

Test	Method	Specification	Result	Conclusion
Appearance	Visual inspection	White to off-white lyophilized powder	White lyophilized powder	PASS
Identity (mass)	LC-MS, ESI positive	Theoretical ± 1.0 Da	24,814.2 Da	PASS
Purity	RP-HPLC, UV 214 nm, area%	99.0%	99.10%	PASS
Largest impurity	RP-HPLC, area%	1.0%	0.37% at 6.24 min	PASS
Water content	Karl Fischer	5.0%	1.8%	PASS
Bacterial endotoxin	LAL, kinetic	≤ 5.0 EU/mg	0.21 EU/mg	PASS
Sterility / bioburden	USP <71>, membrane filtration	No growth after 14 days	No growth; conforms	PASS

1HPLC chromatogram

Data file: GDF8_PL-2609-034_20260918_01 · Column C18, 150 × 4.6 mm · UV 214 nm

Baseline uncropped; main peak and impurities labeled with retention times. Peak table on page 2.

PrymaLab

Certificate of Analysis · continued

GDF-8 1 mg · Lot PL-2609-034 · Certificate PL-26-00034

Lot PL-2609-034

Method, peak table and approval

2HPLC method · GDF8_PL-2609-034_20260918_01

Instrument

Waters Alliance e2695, SN E2695B742

Data System

Empower 3, Build 3471

Detector

Waters 2998 PDA

Detection Wavelength

214 nm

Column

C18, 150 × 4.6 mm, 3.5 µm

Column Part / Serial

186003326 / USHX18211

Mobile Phase A

0.1% TFA in water

Mobile Phase B

0.1% TFA in MeCN

Flow Rate

1.0 mL/min

Column Temperature

30 °C

Injection Volume

20 µL

Run Time

10 min

Sample Diluent

Water, 0.1% TFA

Sample Concentration

0.5 mg/mL

Blank Injected

Yes

Reference Standard

In-house GDF-8 reference, lot PL-RS-GD8-01, RT 7.04 min

3Gradient program

Time (min)	% A	% B
0.0	95	5
3.0	95	5
7.0	55	45
8.0	20	80
9.0	20	80
10.0	95	5

4Peak table

Peak	RT (min)	Area	Area %
1	5.62	10,750	0.25
2	6.24	15,910	0.37
3	7.06	4,261,300	99.10
4	7.68	12,040	0.28
Total		4,300,000	100.00

Threshold 0.05% area · Blank subtracted: Y · Purity = main peak area ÷ total integrated area × 100, to two decimals; main peak shaded.

5Identity by mass spectrometry

Instrument

Waters Acquity SQD

Ionization / Mode

ESI, positive

Observed m/z (charge)

1241.7 (20+ [M+20H]) · 1128.9 (22+ [M+22H])

Deconvoluted Mass

24,814.2 Da

Theoretical Mass

24,814.0 Da

Difference

+0.2 Da (8 ppm)

Data File

GDF8_PL-2609-034_MS_20260918_01

Acceptance

Within ± 1.0 Da

6Additional tests

Test	Performed by	Date	Report / file
Water content	PrymaLab	2026-09-19	RPT-KF-PL-2609-034
Endotoxin	PrymaLab	2026-09-20	RPT-ET-PL-2609-034
Sterility	PrymaLab	2026-10-02	RPT-ST-PL-2609-034

A test with no row here was not performed on this lot. Outside-laboratory reports, when used, are attached and named below.

7Review and approval

D. Reynolds
Analyst · performed the testing
Date: 2026-09-18

S. Calloway
Reviewer · checked against raw data
Date: 2026-10-02

M. Phelps
Lab Director · approved for release
Date: 2026-10-03