Antibody FR is the skeleton region. There are about 1 10 amino acid sequences in the N-terminal of immunoglobulin H and L chains, while other amino acid sequences are relatively constant. Accordingly, light chain and heavy chain can be divided into variable region (V) and constant region (C). VH and VL. There are three regions with highly varied amino acid composition and arrangement order, called hypervariable region (HVR) or complementarity determining region (CDR), which are CDR 1, CDR2 and CDR3 respectively. The amino acid composition and arrangement order of the outer region of CDR are relatively difficult to change, which is called skeleton region (FR). VH and VL have 1 13 and 107 amino acid residues respectively, which constitute four FRs (fr 1, FR2, FR3 and FR4 respectively) and three CDRs (CDR1,cdr 2 and CDR3 respectively).

Fr is the unit of catheter, originally the unit for measuring circumference. It was invented by a French doctor and is short for English and French. The number after Fr represents the circumference, for example, Fr 16 means that the circumference is 16Fr. Because 3F= 1mm circumference, F≈ 1/3 circumference ≈ 0.33mm .. circumference =π(3. 14)× diameter, diameter ≈ 1/3 circumference =F× circumference/1. Based on this, we can calculate the catheter diameter fr16 =16× 0.33 ≈ 5.3mm. ..

FR model:

FR model is the abbreviation of instrument. The products of FR model are:

1, tensile machine, tensile testing machine, universal material testing machine, tensile and compressive material test series: physical tests such as tensile strength, tear strength, peeling strength, bending die and three-point bending can be done.

2. Environmental test series: such as constant temperature and humidity test box, high and low temperature box, salt water spray, low temperature cold resistance, aging resistance, yellowing resistance and weather resistance.

3. Paper and carton inspection series: such as package compression, package drop, ball impact, ring compression strength, rupture strength, etc.

4. Rubber, plastic and leather shoes: finished shoes such as vulcanizer, rotor-less vulcanizer, bending-resistant, flex-resistant, wear-resistant, friction decoloring and waterproof.

5. Wire, cable and electronic equipment industry: comprehensive testing machine resistant to combustion, swing, sudden pull, elongation, wire bending and voltage.

6. Common tool series: projector, image measuring instrument, hardness tester, needle detector, push-pull instrument, caliper, electronic scale, balance, color difference meter, thickness gauge, moisture meter, melting point meter, etc.

7. Plastic testing machine series: melting instrument, impact testing machine, Vicat softening temperature testing machine and LCD impact testing machine.

References:

Baidu encyclopedia-FR